Okay imagine dkbk personality swap BUT !! their roles remain (relatively) untouched.
Like, Midoriya (5 years old) takes one good look at Bakugou's name and goes:
"Huh, '勝' kind of looks like '駄', right?"
"Then, that's it! From now on I'll call you Dacchan!"
"Well, your quirk's pretty much wasted on a coward like you! It's fitting, isn't it?"
But since it's their personalities swapped, and not their ideals, I don't think Midoriya would bully Bakugou -- just tease him. Bakugou on the otherhand might start to think Midoriya only hangs out with him out of pity or something (because he has no friends and is midly terrified of his own quirk) but Midoriya would quickly disenchant him from such an idea.
"Tch, are you stupid?! Since when do I do anything I don't want to, huh?!"
"N-never! 'Zuku is too steadfast to be pushed around like that!"
"Exactly! Now stop being such a whiner. You really are a crybaby Dacchan, huh?"
I don't know how far I want to swap certain aspects, like cursing or muttering, but it could be altered to an extent. Midoriya is still quirkless so he'd for sure still be doing quirk analysis, and while I don't think he'd be popular -- again, still quirkless -- I do think he'd actually stand up for himself against bullies. Bakugou probably tried to help Midoriya at some point and, while it most likely worked, he definitely got hurt which Midoriya wouldn't appreciate.
"So you think I can't handle myself just 'cause I'm quirkless?!"
"Th-that's not it at all! 'Zuku's amazing and super strong no matter what! I just- I couldn't stand by while 'Zuku was getting hurt! I refuse!"
"Ugh, damn worthless crybaby..."
Anyway, I think Midoriya would try and look after Bakugou but would never admit to it. He still runs into danger (the Slime Villain) and gets OFA, but his -- and Bakugou's -- UA dynamics would definitely be different!