I don’t know what Whirlpool’s warranty is these days, but they used to warranty the sealed system for 5 years. That covers the compressor, condenser, and evaporator. They also hated to have unhappy consumers. Not being able to hear it myself, first check and see if the noise isn’t coming from either fan motor. Make sure the evaporator fan isn’t hitting ice and causing the racket, or the condenser fan groaning. Make sure the condenser is clean. Locate where the noise is coming from before you call them. I doubt they will foot the bill if it’s a part out of warranty. If none of the above applies, I'd lean toward the sealed system. That fridge should have many years of good quiet service ahead. Definitely get a different technician this time. That one sounded too lazy to dig in and find the problem.