Motivation is good.but discipline is better, lasts longer.
@OP, get tested for low testosterone at your GP, HRT gave me back the energy and drive I had as a teenager.
You've gotta find a way out of the anhedonia in my experience,.new experiences are a good way to do it.
For me the list is pretty clear
#1 Final Fantasy IX - cliched story of a guy chasing the princess but so many twists on the way, and even some philosophy, huge story and so much to do in the game. Much more vivid characters than 7 and by far the best soundtrack of any game in history.
+1 for rimworld and valheim
Civ4 has gotta be pretty small too, i prefer it to the modern ones
Siralim ultimate has probably a thousand plus hours of gameplay, but it tales a certain typ of person to enjoy it