I just commented in another thread about this type of situation - I worked in, and loved working in, auto shops - performed really well (ASE Master Tech, shop foreman) but after a couple/few years I would invariably "burn out" for no really identifiable reason (I still LOVED doing the actual work) and switch careers to I.T. - which I would also burn out on after a bit. I've switched between the two four times (I'm 50).
I only recently decided to see if I actually had ADHD because when I was younger, it wasn't really recognized as a thing (unless you were REALLY bad in presentation) and was instead viewed as "you're gifted but you just have no self control" which lead to learning some tools to mitigate that problem, but completely ignored others - so it turns out the executive dysfunction is what's caused me real issues over the years.
I've never been a fan of "magic pills" and so I always thought medication would simply be a band-aid of sorts, based on my understanding of ADHD (until recently) was generally what I had heard when I was younger. I never really looked at it as an option until this past year, but now understanding better the function of it, I know that used properly, it can likely address the issue without necessarily becoming a crutch. The comparison I see mentioned often about "a diabetic can't just overcome the need for insulin in order for the system to work" makes sense in general - if you have a functional issue going on in your brain, it's not likely to repair itself.
So while I fully support your wanting to avoid medication (for whatever reasons) as a path to address the issue, I would at the same time still encourage you at least taking a closer look at medication for ADHD, and specifically, how it works. If your work situation is anything like what I've lived through multiple times, there is likely no "trick" that'll reliably get yourself re-interested in it, because it won't really be addressing the source of the problem.
All of that being said, even if you do have an issue which medication would address, the final outcome could still be that it is, in fact, time to move on to something else. I just wrote this up because it smells a little bit like what I've been through and so wanted to share. A final point I will make is that even though I would tire of the shop, whenever it happened in another situation/career, I always know if I went back, it would be glorious - at least for a time. That's what magnified to me (finally) that I'm the part of the equation that's an issue and not the work.