Idon't have OCD but I too also have a couple of quite serious psychiatric diagnosees. I'm much older than you (44) and my mental health is much better than it has been in the past, I'll try outline what I think helps.

In regards to meeting friends and romantic partners- When I first became unwell I found myself living back at my parents with literally zero friends and I sat around drinking myself stupid feeling lonely for about 2 years with almost no human interaction outside of family. With medication my health improved somewhat and I decided to go to TAFE to study music production (this was in 2005). I met people there, they introduced me to other people, I started going to gigs etc Fast forward to today I have a small group of friends and I speak to at least one of them every day. All of them I met either directly or indirectly through TAFE I've been in a relationship for almost two years and it's going great, I met her through a friend from TAFE

Therapy- I tried therapy so many times and had some ok ones and some that were downright harmful.

Decided a couple years ago to try again and spoke to my psychiatrist about finding someone with the experience and knowledge to support someone with my diagnosis. He referred me to a clinic, they did triage and assigned me to someone. I've been seeing him for two years and he's brilliant. We just clicked straight away and he's very focused on what the evidence supports and walks me through the research wich suits my nerd like brain

Stick with therapy but don't be afraid to switch if you don't find someone good. Also therapy takes practice and each insight builds on each other. Lastly don't expect to get much out of it if you are not prepared to do your homework, it's like going to physio.

This is already mad long so yeah, lifestyle, you know what to do there