Armchair psychologist here: Have you tried games? Either physical (e.g. sports) or digital (ideally single player, desktop computer games)? If you have fun, it is much easier to get into a flow state.

Yes, I play about an hour a night, but I don't really get into the flow of them, I'm usually checking my phone during loading screens or cutscenes. I'm sure physical sports would be somewhat easier. Making music can sometimes do it in the right situation. The problem is though that I can't make it happen at will, but I really would like to be able to concentrate on my work as a physicist, e.g. reading a paper even if I'm not that interested in it personally is quite important to be able to do but it takes me days.

It might help if you introduce more things to focus in and out on. I find that when I'm playing a game I'm not as interested in/has down time, by having something like music playing softly in the background, I'm able to focus in better during slow periods.

Some amount of LoFi beats, classical, or music in another language might help a bit even if you feel you need to 'focus in' by just providing a bit more stimulation? I find that without music it's much harder for me to enter my flow state when programming even if I 'stop hearing' the music once I get into what I'm working on.

But everyone's different, that's just something that works for me, but I hope that you keep up the hard work. Focus is hard, and you're taking some important steps to try and restore yours.

I already listen to techno when I'm working. The problem is that when I'm not intrinsically/emotionally interested in a task I struggle to force myself to focus on it. It seems like focus is not something I can control, I always would rather distract myself with low effort dopamine fodder (youtube, twitter, reddit, hacker news, tiktok, looking for new music to put on, etc.)

I've been trying for years. I was introduced to technology very young, and have been using the internet since I was about 8 to 10 years old. I'm 27 now, I've been seriously trying to improve my focus since I was about 22, but nothing stuck. If intensive meditation cannot help me, I'm not sure if anything can, except maybe some kind of drugs.

Have you talked to a doctor about ADHD and possible treatment methods? The pharmacology behind prescribed stimulants work to flood our dopamine receptors greatly weakening that urge to check our phone for those sweet, sweet, notifications.

I'm British, and in the UK it's extremely hard to get adult ADHD diagnosis. Basically you have to go to a private doctor and even then they are quite strict. Due to my high academic achievement (doctor in quantum physics) they will probably say I don't have it. The situation there for adult ADHD is so bad that basically I just gave up on the whole thing and decided that I didn't have it.

I live in Germany now, but unfortunately I don't speak German anywhere near well enough to get a consultation.

Are there no English speaking doctors in Germany?

A specialist in the UK might be worth talking to. You’ve tried many natural alternatives and nothing helps you with your work. Meditating every day for a year is a big accomplishment and it says a lot for it to not help.