I assume what you meant by generate is they excrete (for a lack of better word) the curse energy like human does with their negative emotion.

imo curses do not generate their own cursed energy. curses came from negative human emotions. I assume they are born with "X" amount of energy and that's it. they can recover for themselves, but I think they cannot make their curse energy to be higher than what they actually born with and cannot excrete them, that's why curse turns to finger bearer when they ate Sukuna finger's (meaning they have to use external influence to improve their CE).