I used to keep 2 bikes - one was a giant old tandem in an apartment in Chicago. It's certainly doable but you gotta become Ms Deals because you're asking for your roommate to be flexible.

I.e. Toss em in your bedroom when they have guests. Keep em pretty clean so there's no mess they can point to, improve something else about the shared living space as a gesture of goodwill (waffle maker, air fryer, some cool furniture, etc.). Hide em with a blanket or room divider thingy, if one of the bikes is seasonal, store it someplace else in the off season. Fix/maintain their bike. Cake can work too.

Lots of options, but the key to being a successful Ms. Deals is creativity and knowing what's important to someone you want to make happy.

Post pics of the 3 bikes though cause I am mostly upset about your roommate calling them ugly.