https://www.mangago.me/read-manga/tales_of_seol_gongchan/
This one is not listed as psychological for some reason, but a couple chapters in and you'll agree that it should have been
https://www.mangago.me/read-manga/please_pay_attention_to_me/
This was a resent short read, also not listed as psychological, it kinda have the same elements and I surly did experience the same kind of rollercoaster emotions with it
https://www.mangago.me/read-manga/stalker_s_game/
You probably came across this one or at least heard of it, and if you haven't read it yet the I suggested giving it a try, especially if you feel like reading something heavy

I've been having a hard time lately to find something new to read. So far, my favorite genre is Psychological and "Red Mansion", "Checkmate" etc. have been my favorites so far. Could you maybe suggest something interesting and where the characters are complex? (Only BL Manhwa if possible). Thanks in advance!