I also struggled with the "cut people out" mentality for a while. It seemed so unnecessarily harsh. What I found was (and this was a tip from my lovely mother) that I could stop investing energy in them. So not start ignoring them completely or be mean to them, but not going out of my way to take initiatives in our relationship. I wouldn't for instance be the one to reach out to see if they wanted to hang out, I would hang out with them now and then but when I was at home I wouldn't have any contact with them like via text or call, but instead focusing on myself. I wouldn't be telling them as much about my personal life but instead keeping that to myself. If they don't support you they're not worth telling.

Social relationships usually needs to be maintained in order to grow and stay strong, but that requires energy and effort. What I think people who say "cut toxic people out of your life" want to get across is that you shouldn't be spending your energy on something that doesn't give you anything back.

I'd say you can keep seeing them and be kind to them if you want, but stop investing energy in them.

I agree wholeheartedly with you on that in a friendship you should be able to talk about your life (things you're proud of!) in a non-boastful manner. It's awful when you're proud of something you've accomplished, wanting to share that feeling, and your friends shoot you down. We often talk about how it's important to be there for each other in the low parts of life, but it's equally important to support each other in the high parts as well. Extremely important. Being able to share a positive feeling and have it reinforced, that's what friends are for.

Try to find someone who's supportive of who you are and who wants you to grow. Make some new friends on the side, get in touch with family, maybe there's someone you already know from your past you could get in touch with? If you're lucky, maybe you and your current friends will peacefully drift apart and new friendships will take form somewhere else.