With a bit more info from I will do my best to see if I can help you out "some"
1. So that you know the the different #'s 062 and 063 - just mean the motor connectors are different (and different connectors also requires a small manufacuring change to the 063 case fro m 062) - G062.1000 or G062.1000 can have the exact same Performance Spec.
2. w/Hub motor like G062.1000 - you would buy a "kit" from China with 30A-controller/Display/BrakeCutoffs/Wiring -+ buy the Hub Motor + plus buy decent 20AH 48V-52V-60V Battery using 21700 cells. My opinion 72V is a bit too much with Hub Motors
3. If you want "more Power" and "more Acceleration" and "a bit more speed" then go with a Bfaang or CYC mid-drive kit you can run that up to 72V if you want.
4. If this is your "First Build" - if in your like you don't have the space to build - or you don't have a full week to set aside for the build - then frankly you might consider "having it Built-For-You".
Having it "Built-For-You" it's the Builders job to make sure the components integrate well for both effectiveness and for reliability especially with your 'First Build" the most excitement is Riding the dang eBike !