i've seen retired pros talk about how once you start to hit your mid to late twenties your body just simply doesn't have the same reaction time and movement speeds it had when you were younger. just look at the ages of all the pros in most competitive games. there is a reason they are all so young.
the best you can do is try to take it a little less seriously and focus on having fun. try to find positives in your failures and celebrate them. compliment your opponent at the end of a loss!
find ways to practice and do warm up arounds before your gaming session. for example if you're playing shooters look for a 3D Aim Trainer and play that a bit before hitting the battlefield. playing a moba? fight bots for a round or two.
if you're playing for extended hours, get up once in a while and walk around. hope any of this helped. best of luck gamer bro! hang in there
if i had kids and had to choose, im probably going xbox for the amount of money id save with games pass.