Welcome to the forum! Hope you aren't scared off birds forever! For the few times a well trained bird will bite you in it's life (it does happen), the benefits of a loving, intelligent, lon-lived companion FAR outweigh the occasional chomp. I'm not sure how much damage a medium bird like a red belly can do, but I would imagine not nearly as much as the bigger guys.
And if I can add my opinion- worse biters are cockatoos! Latch on like a gila monster and grind right down to the bone until you physically pry them off. Kiwi's bit me pretty viciously before, twice in the face, but NOTHING compared to bites I got from Alfie the G2 in the past

His beak was like a pair of razors and he doesn't let go! My mom got bit so bad one day she needed stitches and it caused permanent nerve damage in her finger. I don't mind "bite and release" birds, but ones that hang on- not for me:52:
The Red Bellied can't do the damage of an Amazon, but from what I've heard, Poi's are stronger biters than other medium sized beaks (and ALL parrots bite hard). I say "from what I've heard", because fortunately I haven't been bitten AS hard by any other bird I've had including a couple larger.
When I was a kid my dad (briefly) had a Cockatiel that my aunt pawned onto us. I remember he said it punctured straight through a leather glove and into his finger, and that's a small beak too!
Poi's will definitely do the 'latch on and not let go' you have to pry them off your bloody flesh. Whereas Raven the Pionus will bite and release. I'm not sure how he'd do it after maturity though. Their display is a lot like an Amazon and they're related so I'm guessing they do whatever zons do. Do Amazons tend to hang on and grind?
Yeah, I keep telling Don about that aspect of Cockatoos after maturity, and I don't know if he fully believes me since he loves to see the cuddly baby Toos in the store. He wants one but that is a species not for us personally. I tell him Noooo!