My local trails are twisty rocky singletrack so 26 inch wheeled bikes with short or no travel bikes are fastest and most fun. My ten+ year old bikes are gettng a bit creaky and likely unreliable for a multiday epic but for my riding they are fine.
If I cut back on the road riding and plan more rides off road and away from home then likely I’ll invest in a 29 inch wheeled bike or a modern decent travelled full suspension bike.