I had very similar thoughts this morning while out on my bike, unfortunately I’m 2, 1/2 yrs shy of 50, and went with a road based bike.
But tourer/everyday work horse or a less used audax’esque beauty.
Nope I couldn’t decide either, and that’s before brakes/drive train etc.
Sad though that my first, cycling, love MTB’s got ignored purely because there isn’t a standard wheel size that I can believe willl be available for the next 30yrs.