I'm almost 50 (and I played a lot of quake 1,2,3 back in the day) but I don't do FPS anymore. Physically I probably overdid it in my youth as now I have some numbness in both index fingers. I also can't hold down the right mouse button constantly as some MMOs require to pivot the camera (WoW being a prominent example, unless they changed it, though there used to be an addon that would do it, anyway I don't play WoW because of the sub.)
I don't like to put too much time into gaming these days, I have bursts but then take many months off. OTOH its better than reading the news or pointless or rage-inducing comments on social media, or even here at times. Since I can control the gaming experience I can make it pretty much autopilot so I don't have to worry about blood pressure spikes.
For you or anyone else that has numbness in the hands, a neck x-ray could be enlightening. As we hunch a lot we start to deform the cervical spine into pinching the nerves that run all the way down our arms into our hands. Problems in the neck area often manifest as symptoms anywhere in the hands, arms, and shoulders. Treatment varies, but I personally find a cervical dennerroll quite helpful.
Two severe pinches on the cervical spine here. Always start with a physical exam and let the doctor order the appropriate imaging. X-rays will not likely reveal anything going on with the spinal cord itself, that is in the realm of MRI or CT. A good neurosurgeon will know what to order.
I also have problems with games where you have to hold the mouse buttons down extended periods. But there is help to be had, especially if you have problems working [1], but also in general [2]. It's usually a few meetings where you get to do some movement while they feel your joints and then you get some exercises strengthening muscles or stretching sinews. Picking up archery might be good for your shoulders and posture too :-)
I don't like to put too much time into gaming these days, I have bursts but then take many months off. OTOH its better than reading the news or pointless or rage-inducing comments on social media, or even here at times. Since I can control the gaming experience I can make it pretty much autopilot so I don't have to worry about blood pressure spikes.