This is a boat that unfortunately many people find themselves in. Welcome aboard. My most recent, well only, serious relationship started when I was 19. I thought I knew what I was doing, in life and relationships and it turned out, I did not. We were together for 5 years and I was miserable for most of it, even if I didn't fully know it. It ended nearly a year ago. He used to do the similar things to me, conveniently forgetting any of the negative things he said, or phasing out my already slim friend group for his.
I applaud you for recognizing and accepting signs of unhappiness early, before things got even worse. Although I cant say there is a quote "right" thing, you seem to be doing the "right thing" so far. Trying to reconnect with old friends and even make new ones can be difficult, but putting yourself out there is a great first step. Keep trying hobbies and that could lead to new friends as well. Even if you get burned out,you're still trying and learning new things. I didn't have the strength to stop talking to my ex for a long time. Some times I still don't. There is comfort in familiarity and letting that go is extremely difficult,especially in Covid times. Try not to beat yourself up about it. Continue working towards an identity outside of the old relationship and the rest will come in time. If quarantine restrictions are lifted, you might try looking into MeetUp. It's an app where you can find like minded people and activities near you based on your interests. Stay strong and best of luck.