eBike technology explained

Hey everyone!

I've been looking at upgrading my old commuter eBike (a pretty basic hub-drive model) and browsing all the new tech out there, and honestly, it's a bit overwhelming! From torque sensors vs. cadence, to different motor types (mid-drive, geared hub, direct drive), and battery chemistries – it feels like there's so much to learn. For those of you who've really dug into the "eBike technology explained" side of things, what's one piece of tech you think makes the biggest difference in ride quality or efficiency, especially for someone who does a mix of city riding and weekend trail exploring? I'm trying to figure out where to focus my research for my next purchase.