I’m not seeing anything out of place on the bucket control.
You around saltwater? Could be cause of your rust. I’m in freshwater and don’t have that issue.
Personally I would pull the handle and replace the bolts and washers that hold it. Probably getting rust from cheap washers or cheap bolts. Being a tow point and grab handle rust is bad and can lead to breakage given the right torque ( ie dragging a tube etc).