Antibiotic Suggestion:

[hard quartz]

Maybe a mechanic that would clean up or remove unused hearts if left alone for a certain amount of time

[lapis root]

Yes

[hard quartz]

enter the gungeon levels of annoying

[hard quartz]

Another antiobiotic suggestion:
A weakened boss creature (maybe unkillable) will slowly follow the player across the map

and be a big nuisance

I played alot of deep rock galactic, and some map modifiers has that exact mechanic

[terse panther]

the immortal snail