Now that I've got multiple ebikes as backups, I can tear down my primary one to improve various things. I've decided to concentrate on the rear rack, the freewheel, new chain, enable regen (using one ebrake on the front brake), and add a suspension seatpost.
I decided to go with this aluminum back rack (Generic pic from Amazon):
Next weekend I'll add another torque arm (from Grin Technologies) to the front hub motor, for 2 total.
The sound and feel of regen caught me by surprise. The motor now engages (effectively in the reverse direction) whenever I brake the front wheel now. I ride pretty aggressively so this happens constantly. It's like having 3 brakes.