I appreciate that - exactly this is something I've been working on, and a lot of the time it's fairly successful. But this is the ADHD curse - it's all too easy to feel rejected and lonely because on this occasion I have no plans with anyone. The negative thoughts manage to persist much longer than the positive.
The Now always takes precedence, always dominates.
Happy belated birthday! That sucks - I know. I've been struggling this weekend with that perpetual loneliness. I have friends in this city, live with several in fact, but all too often when the weekend comes around everyone has made plans without me and I'm sitting at home on a Saturday night watching shows. It's easy to interpret it as a judgement on myself, that I'm somehow not sufficient ( which I did for years before my diagnosis). It's still not easy, and if I had an answer for you on how to deal with it I'd be a much happier person.
I try to let it just wash past me, accept that we have different patterns which often leaves these large gaps. With a couple of major exceptions, I've learned the only people I can rely on socially are other ND folk - and we're infamously flaky to start with!
I can't really offer advice, but know that you're not alone, it's not just you.
When it hit me, it hit me like a truck. I was diagnosed around 35, and after bouncing through the relief, euphoria, and anger (pretty much as OP described them) I was hit with a crushing sense of loss - I literally felt as though someone close to me had died - but who? I was fortunately in therapy as part of my diagnosis, and it took the doctor to say "Who died? You did." for me to understand. The person I lived my entire life as had ceased to exist - that was a very unhappy person, constantly struggling, constantly suffering for reasons they couldn't see. But it was me, and now they were gone. It was a brutal experience, but it gave me the freedom to start redefining my life.
You got this. Adrenaline is fuel for the fire.
I have a Fairphone 4 with LineageOS - it's a couple years old now but runs great. The headphone jack situation was an issue for me too, but I bought a USB-C -> 3.5mm converter for a few euros which now lives in my headphones case, and honestly, it doesn't bother me. Don't let that small point keep you from a good device.