I am torn on this. I get that man has evolved due to the need to overcome. I get that we are shaped mentally, philosophically by our challenges.
I know that I would be happy in retirement on the beach but we are talking about 2 decades, a far cry from "forever."
But it seems we could challenge ourselves in small ways even in perfection- learning an instrument or how to build certain things, then a different instrument and building different things. We could learn how to win auto races or horse races or foot races, then rowboat races. We could sew our own clothing and become skilled at that. To rid the world of large facilities, we could get our own water and food the hard way and dispose of our own sewage and garbage the hard way, so our daily drudgeries become a workout. Sure, tiny goals would become important goals and it may be a bit weird to focus on cutting a half-second off your rowboat mile, but it could be done.
I think I could find a way to "switch it up" over time.
It matters not, though. It's all just a fantasy.