Sounds like I have a pretty similar office job and I used to have similar problems with the exhaustion. There’s a few things that really helped I think. The first was to be more active at work. Obviously there’s a limit to what you can do, but don’t pass up any opportunity to get up, walk around, and stretch your legs. If you can take a break/lunch outside then do that. If you have some days where you don’t have too much work to do and it kinda feels like you’re just sitting there with no sense of time, or you’re just watching videos to pass the time, try to find something to do instead. Pick up any trash/misplaced things around the office, reorganize files, have a chat with co workers. This all helps to prevent the exhaustion, I’ve found. Then, when I’m out of work, I try to have non-gaming things to do. Like family dinners on fridays. This helps me feel like I do more than just sit behind a desk all day every day, and it makes it feel like more of a treat when I do sit down to game. I don’t know if these will work for you, but they’re worth a shot if you haven’t tried them I guess