Like there's always dramas about someone who has the power of seeing dead ppl and solving their(dead ppls) regrets, is there any drama where the lead(s) solve the living ppl's regrets(and there's no death involved at all)?

That's an extremely interesting question...(and most of the ones I've seen involve ghosts and death tbh).

At a guess, I'd say a drama like Knight Flower. I haven't seen it but from what I understand the FL sneaks out to secretly resolve the issues of those around her. You'd be looking at plotlines similar to "Touched By an Angel" (a very old US series I only know of thanks to my mother as it's something she watched from time to time when she was younger).

Possibly....

 Order of the Sommelier? The leads run a bar where the drinks allow people to resolve issues of their past lives (they're reincarnated and alive in the present).

8.2 Byo no Hosoku? ML's cooking helps couples with their problems. It's a BL.

Maybe:
Don't Disturb My Study - FL travels back in time and helps other students with their problems
Hammer Session! - new teacher helps his misfit students with their problems