I went to Ontario local dealer for my 2020 RX 350. Stated the problem and service manager said it would need a replacement assembly without going a test drive. Will cost around CAD 1400 + labour to fix. Since this is not a commonly know issue, Lexus Canada won’t fix and my factory warranty went out so, I would need to pay for it. So, I denied the fix.
While talking he mentioned there might corrosion for a 10 yrs old vehicle but not this new.

 

1400 to fix a shaking left had mirror?

The service bulletin call for 3 bolts and a reinforcement bracket

www.youtube.com/watch?v=ZRcJff22l60