Blooming Panic and MysMe both have a chatroom as a setting. Blooming Panic is a shorter game BUUUT it's completely free, it's not a mobile game so it doesn't need energy or coins to unlock chats, and it has a skip system if you like replaying to get all the ends. MysMe has a more fleshed out story, it's got more content, and it has more romance options (and 707 my ultimate otome bias lol). I don't want to give too much of the story away, but Blooming Panic can have it's dark moments although not as dark as MysMe imo
Jumins bad end is definitely one of my fave ends if you pick it up again, but it's not for the faint hearted :'D
Blue pill. I never want to relive my childhood trauma again ๐ค