Pace 500.3 accessories?

After test riding a few, settled on and just bought my first e-bike (pace 500.3 step over). For those who have the bike, what do you think of the accessories available - are the Aventon brand of accessories the only thing that is compatible? (I’m thinking I would want to at the very least attach a rear rack, and would love to do a mounted folding bike lock, and also considering a water bottle holder) tia for any input.