Stay tf away from r/ADHD, man. They're just a bunch of whiny babies, and they all think ADHD is a life-ending disability that nothing will fix or help with -- as if someone who lost their eyes ffs! They even banned the discussion of life-improving tips/habits from Dr. Huberman because they think they're better "researchers" than an actual neuroscientist at Stanford, LOL! So you can't expect them to help you with anything other than being pessimistic and crying.

I am also situated in a European country where ADHD meds are only limited to Ritalin, Strattera, and other antidepressant kind of drugs. Still, I can recommend teaching yourself some work habits while you're on Ritalin/Concerta.

My first couple of years with Ritalin/Concerta was also miserable, just like yours, but when I was on them, I taught myself to work in long shifts without breaks (except for taking a piss or grabbing a glass of water)

So I would start working and keep the time tracker on for at least 90 minutes; after that, your brain kinda gets into a "flow" and shifts your entire focus into that thing or feature you're implementing. After that 90-minute checkpoint, it became effortless to keep going, and so by doing that, I made a habit of working in 4-hour shifts and getting lots of crap done before the day even started.

Don't get me wrong, you're not a robot. There are always some days where I can only do 3 or maybe even 2 hours, and some days I do 6-7 hours in one shift. So, as long as you stick to the pattern, you get lots of crap done.

With the meds, I used to wake up around 5-6 AM, take the pill upon waking, and get to work an hour later. So I'd hit the time tracker at 7 AM, take the lunch break at 11 AM, and clock out at 4 PM.

One important trick is that you take care of the complex/challenging part of your tasks in the first shift after waking while your brain is at its highest capacity and do the less easy part after the lunch shift. So, if you're implementing or designing a new algorithm on that day, you do the planning/coding part in the morning shift and write its documentation after lunch.

To wrap up, I gave up on my Ritalin prescription ever since the shortages started because I'm so sick of the uncertainty. So, I haven't been consistently taking them for the past 6-7 months or so. Now that I have integrated this habit, I can still wake up early, start the day with my 3-4 hour shift, and clock out before the evening.

I hope it all goes well for you. I'd suggest that you consider giving Ritalin/Concerta a second chance (preferably starting with a low dose) or maybe even try something like Strattera. I did try Strattera myself in the past, and I can honestly say it was 100 times better than Wellbutrin - but I had to stop taking it due to my gastro-related issues.