Advice on burn out due to ADHD
Fellow ADHDer here, with the added handicap of Severe Anxiety™️
...Okay. Me trying to be funny aside...
First of all, don't take the game ratings seriously. They adjust it to your actual rating and so it doesn't really represent your actual strength at all.
Case in point: a couple of years ago, two GMs proved that game rating is pointless by starting a game together and playing as terribly as possible; they both still got a rating of around 2300. On the other hand, whenever I played a near-perfect game in the 700s, the highest game rating I would ever get was something like 1650.
As for burnout...yes. I have a tendency to play rather sporadically as of late, which can be a bit of a double-edged sword; I rarely tilt, but I also don't improve as quickly as I used to. Still, gaining 30 points very slowly is better than losing 100 points really, really fast.
I don't think there's much that can be done about it, though. Probably the only thing I can say is that you shouldn't force yourself to play when you don't really want to. Trying to play a game when you just don't feel like it won't lead to good results.