Try to think of it as an endless ls-cd loop with tons of automated functionality few keypresses away. Also, please try the type-to-nav mode in nnn.
Also, find/fzf etc. are useful as long as you are not on a slow disk and a mid-range Android device/the Pi. If you are saying you are OK with scanning the whole filesystem every time you are looking for something that can be anywhere under /, I simply don't prefer that.