finding a group wont stick unless you have a level of cohesion, which takes you being comfortable. I agree with your thoughts that can be via a study/hobby/shared interest. But a big bonus of this is your happiness.

Figure what makes you happy, this is not things…this is something that makes you feel peacefull, fullfilled, excited to be part of.

Use your comfort routines, but not to a detriment. Hiding is a comfort but not helpful to the end goal. Test the boundaries of being around people, practice small breathing techniques. There are lots of others just like you doing the same thing despite appearances.

Likewise there is always an arsehole. Everywhere, there is one at school, one at work, one on your street. Learning to spot them and live with them is uncomfy but is a good skill lifelong.

As others have said learning not give a fuck about what people think of you is liberating, however its also a balance as friendships need cultivating, this is part of routine, they are not just a need them when you need them thing.

Good luck, trying is the first step. I hope happiness finds you, and wraps you up.