Noisy sway bar bearings

I have a 2015 Jeep Grand Cherokee 4x4 Laredo Altitude. I was experiencing a squeaky noise when hitting speed bumps. I took to Jeep dealer for diagnosis. They stated I need a new right upper control arm and my bearings were shot on the sway bar. The whole sway bar had to be replaced because the bearings cannot be replaced without replacing the whole sway bar. The cost was absurd so I took to local mechanic. He was cheaper but had the same diagnosis. I had everything replaced. I am still experiencing the squeak when I hit speed bumps. I went back and he greased the bearings again. The noise is better but comes back. If I drive it enough it goes away. The noise comes back the next day. The mechanic claims it may take time because the sway bar is painted and may take time to break in. Any advice? I have a one year warranty but annoyed I spent a bunch of money to fix something that's still there.

Thanks