First thing I would try is changing the radio batteries. Try using regular alkaline batteries. (if you aren't already)

Since everything else looks fine I'd then try soldering some new capacitors to the motor. I've had a few times where I was pulling my hair out trying to figure out why my radio was glitching and it was due to the lack of caps on the motor. The motor creates radio noise and the caps suppress it. I'm not sure what caps you'll need, usually the ESC manufacturer will recommend which ones to use. If not I'm sure somebody here can come up with what they've used.