The good news is the rear freehub is a Shimano compatible splined freehub, with a SRAM PG cassette on it. It's more money but even going to Deore 5100 would only be $100 or so with the cassette, shifter, and rear mech, and it has the shadow+ clutch to prevent chain slap (the switch). As for shifting under power, I have two ebikes with gearsensors and I never trigger the sensor, I usually coast while shifting and that muscle memory is automatic. Since at least my generation of X1 has a CANBUS controller, existing gearsensors won't work, so it's good that I can train my legs to do the right thing.