Not only can you have all the OCs you want, but you can have all the self-inserts you want too!
You can have various different versions of yourself, and pair them with the SAME blorbo if you want! You can poke, prod, separate and mix up all the parts of who you are, with parts of who you want to be, and smooch fictional characters all day long (or kill them, or hang out with them, you don't have to smooch, I just say that cause I like smooching).
You can have one OC that never changes, or one OC that has a bunch of different hats depending on the fandom they're in. Or 100 OCs all specifically created for 100 different characters or worlds.
You can ship your OCs with your own OCs, and even your self-insert too! Blorbo optional \o/
It's all legal.
Totally valid.
100% coverage by the imagination and creation warranty.