HA !!! I TOLD YOU GUYS BECOMING FRIENDS WAS MERELY THE FIRST STEP TOWARDS LOVERS !!
(Why does he think he’s disliked tho ? Did I miss a chapter/flashback or something ?)
It's not that he thinks he's actively disliked -- His self esteem is just so bad that "not being disliked" is the baseline he thinks he has to aim for, rather than "being liked". Basically he thinks that not giving people a reason to dislike him is the best he can hope for.
This is also why he still thinks he only just made his first "official" friend, not realizing that he's had a decent group of friends for quite a while now already. Their friendship, in his mind, is likely just them being nice because he's a classmate or the class rep or whatever. Which is allllllso where he believed he stood with sasaki all this time. "we're class reps, so
of course we had to get along; I shouldn't get ahead of myself" kind of thinking.
Sooo yeah. It's fair of people to get frustrated with him because of how glacial he's making the pace, but it comes from him having a deeply flawed self-image to begin with, which isn't something that's easily solved if the other people in his life aren't being entirely straightforward with their own feelings either.