Lost friend group and not sure how to fix it

This is going to be a long post as it’s over the course of a year this has happened

TLDR: friend group has followed one friend who doesn’t like us anymore and called us toxic.

However you kinda need the context for this to make sense ^

I’m coming on here to get some alternative opinions as ofc I’m biased.

Over the course of a year I’ve lost 90% of my friend group. Last February I went out with friends everything was great and we met up with a guy who we all knew for years but hadn’t seen in a while.

We hit it off a lot and I had a birthday party coming up the same month and since everyone was talking about it I invited him. He said yes and after we hung out that weekend we started talking online, he asked me out at my party I said yes.

Over the next month I notice one of my best friends not really being as chatty or asking to hang out very much yet inviting everyone else round, we live close so I was always allowed around but he never invited me and I just shook it off cause he’s obviously allowed other friends right. The next month we get the whole group together to go to the park and said hey we should hang out it’s been a while. He said with his new house he wasn’t allowed many people round so he can’t today so I moved past it and when me and my bf were deciding to get a taxi or call my mum to go home, I heard him invite everyone else around to his house there was 12 of us but only me and bf weren’t invited.

Over the course of a year he has stopped hanging out with us and stopped joining discord calls for gaming although we used to do this every single night. At any hangout we managed to get him to go too he said yeaa we should hangout I’ll invite you guys round. Then he never does but then dodges my attempts to hang out.

Now more recently half the group has gone with him and said we are toxic and we should speak to him about what we’ve done yet when we try he blanks us now.

Context of the friendships: he knew my bf and introduced him to the group he then stopped inviting him out as much and told us he was too busy for the group without even asking him.

Me and him were best friends and in a little close knit group of other best friends. The year before so this was 2024 he admitted to thinking I was hot and we said we would just see where this takes us the next time I hung out with him he tried doing the yawn trick and I immediately cringed away and told him that night nothing will happen between us as I just see him as a friend. He was perfectly fine with this and it was like 8 months before this party.

Another friend liked me and I let him down easy and he was fine for a few months but once I got with my bf he straight up blocked me.

I’m not sure what we’ve done wrong at all and why most of the group are just following him they won’t talk to us anymore cause they basically had to pick a side.

Is there anything we can do to salvage this as ofcourse I’d never want to lose my friends. It’s been very lonely losing so many friends but there a few who have stayed and can’t get why this has all happened either.