How to deal with not knowing whether I’m sinful for an action or not?

Asalamulaykum Warahmatukahi Wabarakatuh! I sometimes do actions that I am later unsure if they are sins or not, or do a haram action in a way that I do not know if I would be sinful or not (not going into specifics so that my actual question can be resolved). What I want to know is if I should still do repentance even if I do not know if I’m sinful or not. And if I do, and the thing happens to not be sinful, is there any bad on me or of the like? Is there any good deed I gain? Yes, I’ve seen https://islam.stackexchange.com/questions/73500/what-to-do-when-you-arent-sure-whether-you-committed-a-sin-or-not , but the answer given seems to only relate to evil thoughts that come and go. Jazakalakhir!