In general I would say this is a common experience around this age, at least in western cultures.

However I think there is no rule to life, friends depend on a lot of things, from both sides, so they can change throughout your life. It is up to you to try and foster the ones you want.

I’ve improved my life quite a lot but it’s hard to give advice to others.

The comparison mindset is really bad though. It literally doesn’t matter what another monkey on this planet does. Your thoughts about how to improve your life are ones you have to discuss with yourself (maybe guided by a therapist). There is no wrong way to live but you have to make the choice on how you want to.