How to balance a bike?

Hello, i was searching for quiet a while for a good answear to this problem and the two solutions i found were using PID or making the bike like a sphere (what i understood) but i dislike both of these solutions first because i heard that PID is bad for things like slopes because it messes with the calculations and stuff and it’s also hard to setup and for the second one i don’t want my bike to feel sloppy so any advice would be welcome