To better understand the context, I'm creating cursed prestige classes for 5e and I want to make sure that each class has weaknesses (because they are curses, the weaknesses will gradually fade), for now the monsters I have in mind for the classes are: werebeast, wendigo, vampire, lich, zombie, skeleton, mummies, ghost, banshee, dullahan, devil, angel, chimera and skinwalkers (although these last 3 I still don't have a precise idea on how to treat them as curses).

(Prestige classes were a concept in older versions of Dungeons and Dragons. Sadly these concepts have not really been ported over to 5e yet. The only prestige class, AFAIK, is the [Rune Scribe (https://media.wizards.com/ 2015/downloads/dnd/UA_Rune_Magic_Prestige_Class.pdf).Prestige classes are just fancy names for "classes that you have to meet criteria for", they haven't been removed from 5e, just like they haven't been implemented, they don' t inherently conflict with the concept of subclasses)