The four big names to look out for when chosing an e powered bike
Yamaha
Bosch
Brose
Shimano
All v close in performance and features, Brose possibly quieter marginally. As mentioned avoid the ebike conversion kits if possible. But if you do then as long as you're mechanical/electrical minded shouldn't be too much effort, there's just the safety factor does it stop properly etc as you're merging epower with a normal bike. Ive been tempted to build my own downhill 4000w ebike but im out of space for any more projects as im rebuilding a sit on mower quad bike and some cars!
Ive had escooters for a while, the etwow the xioam m365 etc they're great for commuting etc, but beware of battery life and battery failing, cost alot to replace.
Ebikes are great though with pedal assist etc, they give you so much more range and fun at the same time staying fit, thats gotta be good.