I find myself in a similar spot Big Ron lmao. I find I can get by on my opening knowledge, and if it's a long drawn out boring end game with 4 units each, that way I can old man them to death, that's easy to manage, experience counts for something there; but those crazy middle games with units flying everywhere, all kinds of tactics and dynamism I just get blown off the map hahah, hands can't do what the brain wants and the eyes can't even see it lol.
As an old guy myself I feel your pain. I don't have a solution but just chill and enjoy what is still a really cool game after all this time.
Haha nice too see I'm not alone in my boat then, maybe we should start an old vets clan lol