Welcome! Congratulations on your new friend!
I’d give him a little time to settle, like a week or two. I’d still offer whatever crap he was fed before. In other dishes I would offer the better new food. I would still offer veggies every day, and in lots of different ways, cooked, nit cooked, shredded or chopped, or chunks and whole. Also you can share parrot safe meals with him , like some pasta with veggies, or purée some veggies and add to a couple of pieces of pasta fir him. Eat stuff in front of him and gen offer to him.
Parrots love veggies, and they can become great st trying new foods and enjoy it! But at first yiu have to convince them it’s food, because their parents, breeder, pet store , flock didn’t get t chance to reach them this. They learn best from the flock ( you) . Once you get them trying stuff the better they get st trying new things, if that makes sense.
I’ve gotten 3 Quaker’s and 1 GCC , and 2 budgie eating everything that is safe .
One thing that helps with getting to eat veggies, offer in a very wide shallow dish , like a casserole dish. So they can see stuff and pick at stuff . It also seems to help to offer this outside of the cage, kinds of like they did overs it and not like it intruded into their cage... I’m nit sure the parrots view point in this , I just know it works! Just like if you put a new toy in the cage they freak, but outside if the cage they come across something new ( like the remote control) they destroy it with glee....
The other thing that helps, us to st first offer them stuff that has an easy appeal, like I said once they start trying new foods the quicker and better they will get at trying new foods.
I do this by hand, and by offering in the big dish. So first I will offer a seed that they like and say yum yum . ( yiu can say whatever you want but useing a phrase helps make the connection) I will do this a few times, then offer s tinny little cube or sliver of apple. They all seem to like apple. Then I put a slice in their dish. Next I might offer a few fresh off the corn cob pieces of corn, then put a chunk of corn in their dish.. and hot chili peppers seed and all those foods are well liked right out for most birds.. then I offer popcorn, a little scrambled eggs, oatmeal and peas are well liked . I offer anything by hand that I’m having or cooking with that is parrot safe. I try and offer three different veggies at each serving, I do first thing in the morning ( they are hungry ) , then late after ( just what works for me) Even if it seems they don’t like it try stuff, keep offering, sometimes it takes several offeres before they eat it, veggies go in and out if favor around here.
Keep up the habit of offering new foods by hand, they learn that this is food, and to st least check it out, I keep offering high value ( to them) foods here and there to.
Even my budgie will eat with gusto almost everything on the parrot safe bird lists.