I'm very glad you understand where we are all coming from...What you were trying to do by letting your birds live in your home "free-range" and cageless 24/7 was extremely well-meaning and caring of you, you meant to do the best thing possible for your birds, that we all understand. Unfortunately the issue is that you have birds that were bred in captivity, that are tame, and that are living inside a home and in a 'human" lifestyle and not outside in their natural environment. If they were wild parrots living in their natural environments obviously they would be "free-range" because they'd be wild parrots; however, they'd be living in a flock a parrots of their own species, and out in the wild environment with no tame, captive, or human-like habits or instincts like your birds have. If you notice in the wild, you hear the birds chirping and singing at sunrise and see them flying around together after sunrise and all day long, and then after sunset you don't hear or see them at all (except for the nocturnal birds like Owls). That's because in the wild they live the life that is best for them in that environment.
When you put parrots that were bred in captivity and who are tame and used to living with people as their flockmates, and who are living inside a human home and on a human schedule, and even more importantly in a human environment with human possessions and living spaces, they just can't be allowed to be 'free-range" and live like wild parrots do. They must have limitations in captivity for their own health and safety. An IRN, Budgie, or Cockatiel in the wild can't be killed by Teflon fumes from pots and pans, they can't ingest carpet fibers or chew on plastic items, they can't eat fatty prepared foods, they can't get into pesticides or other toxic chemicals, they can't drown in the toilet if the seat is left up. So it's our responsibility as their owners and family to keep them safe and keep them healthy, and that means making rules they must follow, setting limitations on where they can go and what they can get into, and putting them on a schedule that will force them to get enough sleep every single night to keep them healthy.
This also means protecting all the birds in your flock from each other, as if you think long and hard about it, Budgies, Cockatiels, and Indian Ringnecks do not ever live together in the wild, obviously. That doesn't mean that they can't live together in captivity happily and safely, but chances are that any time you bring home a new parrot into your flock, you need to be prepared that they just aren't going to be able to live together freely like you've been doing, it's just not safe, and I can tell you from experience working at an Avian Rescue for years and seeing birds that people surrender that you just cannot let parrots live together that way forever and have them be safe from each other. And that's ALL parrots, even ones of the same species. There's no guarantee at all that if you were to bring home another IRN that it would get along with your current IRN, and the same goes for your Budgie and Cockatiel. Sometimes they do, sometimes they don't, and you have no way to know until they get home together...And even then you still don't know because the dynamics between them can change in the blink of an eye, especially when the largest parrot with the largest beak goes through puberty! So you absolutely must protect all of your birds from each other, and honestly the ONLY WAY to do that is to keep them all separate from each other when you're not home, and to ONLY let them out together when you're supervising them the entire time...
I have a weird flock made-up of several different types of birds...I have a male Senegal, he's the largest and has a HUGE BEAK for his body size, I didn't even realize how large their beaks were until I brought Kane home, his beak is as large as some Amazon beaks...Then I have a female Quaker Parrot as the next largest, then a female Cockatiel, then a male Green Cheek Conure...Then I have 8 English/American Budgie hybrids that are a bit smaller than the Green Cheek Conure, and they all live together in a walk-in Aviary in my home. So I've made sure that my Budgies are not ever able to be in contact with any of the larger parrots, and even then I have to always make sure that the 8 Budgies are getting along with each other and not hurting each other, and they are all siblings from the very last clutch of birds I ever bred and hand-raised. It's 7 males and one female Budgie, and I have to separate the female from the other 7 males every year, sometimes twice a year, any time her Cere turns rough and dark brown, because they will breed with their siblings and the males can become extremely aggressive and jealous over the one female, and they can hurt or kill each other or the female. So she goes into a large cage by herself at least once or twice every year for a month or two that sits next to the Aviary until she's out of breeding-season. As far as my other 4 parrots, they all have their own cages which are very large and full of toys and foraging activities for them to do, and whenever I'm not home they are inside of their cages, and whenever I am home they are all out of their cages. As soon as I walk in the door the first things I do are let my dogs out into the backyard and let the 4 parrots out of their cages. However, that doesn't at all mean that I can just let them out flying around a 1,800 square-foot house with 3 stories and letting them be together. My Senegal does not get along with any other bird in the house, he just doesn't. Whether he's jealous over me or just doesn't want anything to do with any other birds, whatever the reason he just doesn't like them. My Cockatiel is the same way, though she's a sweetheart and can't really bite hard to defend herself against any of the other birds, and the only one she can be with is the Green Cheek; they preen each other occasionally and they don't fight and aren't aggressive at all, but they also aren't at all "bonded' to each other, they simply tolerate each other...My Quaker only likes my Green Cheek, they are the only two of my birds that I would say are even remotely "bonded' with each other, and I don't really think they are "bonded", they simply are able to cuddle-up with each other and sleep on the same T-Stand together, but they still do occasionally fight/peck at each other...I also have a male Ringneck Dove who also has his own enclosure, and he has NO BEAK at all but rather a bill, a soft bill, and he can't protect himself at all, and he doesn't get along with ANY of them except for the very weird relationship he and the Cockatiel have, they seem to love each other very much and are bonded to one another, it's weird but it is what it is...
So that's the dynamic I have going on in my house and with my flock, and even with all the chaos I still have it worked out so that ALL of my larger birds are out in the house with me whenever I'm home. It took a lot of training and time, and a lot of patience from me and from them, but they all figured it out, they all have their own T-Stands in whatever room I'm in so they can all be with me, and they know that they stay on their own stand in the room and play or eat (each stand has multiple toys hanging from it and also a food and water bowl), and the Green Cheek and the Quaker can go and sit with each other if they want to, the Green Cheek and the Cockatiel can do the same when they want to, and the Dove and the Cockatiel are usually together all the time, while the Senegal is happy as hell just being out by himself, playing and chewing and eating and climbing all over me...And the Budgies get to come out every single night for about 3-4 hours each night to fly around the house and spend time with me after the larger birds all go to bed...So you have to figure out the dynamics in your flock between your individual birds, and then you have to get them all into a routine that is firstly safe for all of them, and then that works for all of them. But what you can't do is just leave them all out together when you're not home, especially now that your IRN is going through puberty, because that means all bets are off now. Everything changes once hormones are involved, and the bottom-line is that you've got a IRN with a large beak living with a Budgie and a Cockatiel that he could kill without any issue at all if he wants to, or if his hormones go crazy and he just does it...Puberty changes everything with birds...
So it's all about finding a happy-medium between letting your pet birds all be 'free-range' in your home when you're not at home to supervise them, and having them all locked-up in cages 24/7. Neither one of these extremes are good for them or at all safe for them, and it can be a challenge to figure it all out and get everyone on schedules that work for each of them individually, but it's absolutely not impossible.