If there is any significant voltage drop across a contactor passing 30 amps, the resulting heat build up will burn the contactor open or weld it closed in quite short order. Neither circumstance will subject the compressor to an extended period of low voltage.

"Mechanical relays" may or may not have "short life spans" Many are designed for 100,000+ cycles, some many more.

I suspect this thread is a complete waste of internet bandwidth and support the motion that the OP, having shown us his approach, now treat us to his departure.

My experience with large motors and dirty contacts is that it becomes a race between the motor coming to speed and the thermal time constant of the circuit breaker. If the motor is too slow then the breaker pops, if it comes up to speed before the breaker pops then the current falls to the running current, and all is well. It certainly doesn't run slow, these motors develop maximum torque just shy of the synchronous speed respective of a little series resistance. So I've seen dirty contacts run just about forever, then one day they get poor enough that the breaker blows, and you need to do something about it. I guess what I'm trying to say is that I suspect the dirty contacts are a secondary issue.