eBike technology explained

Hey everyone!

I'm looking to upgrade my eBike soon (currently riding an older hardtail MTB conversion, mostly for city commutes and some light trail riding) and I'm a bit overwhelmed by all the new tech out there. It seems like every brand has its own motor system, battery chemistry, and display features. What are the key technological advancements or specs you look for when buying a new eBike, especially regarding motor types (hub vs. mid-drive) and battery management systems? I'm trying to make an informed decision for my next purchase!