With or without romance?
Anything really
The guy upstairs
Or at least I think that it's also slice of life
this one was good but I don’t know what to say lmao.. but fits the OP’s question very well
Without romance:
https://www.mangago.zone/read-manga/boys_run_the_riot/
https://www.mangago.zone/read-manga/vitamin_suenobu_keiko/
https://www.mangago.zone/read-manga/a_lollipop_or_a_bullet/
https://www.mangago.zone/read-manga/shimanami_tasogare/
https://www.mangago.zone/read-manga/kanojo_to_kanojo_no_neko/
https://www.mangago.zone/read-manga/yagiza_no_yuujin/
https://www.mangago.zone/read-manga/my_broken_mariko/
With romance:
https://www.mangago.zone/read-manga/smells_like_green_spirit/
https://www.mangago.zone/read-manga/watashitachi_no_shiawase_na_jikan/
https://www.mangago.zone/read-manga/six_half/
https://www.mangago.zone/read-manga/three_days_of_happiness/
https://www.mangago.zone/read-manga/17_sakurai_machiko/
https://www.mangago.zone/read-manga/haru_no_noroi/
https://www.mangago.zone/read-manga/othello_shoujo/
Some of the mangas above don't hv the psychological tags in the main tags but I swear every main character struggles with some sort of psychological disorder or has psychologically complicated personalities
https://www.mangago.zone/read-manga/pyramid_game/
Can't forget my fav. Not sure if it's slice of life tho. But ig it is
Make a list bae i'll follow you I swear
Too lazy man I'll have to make like 20 lists for different topics if I do
Aww shucks
Are there any psychological slice of life? Just curious