I started experiencing the shaking on my Vive Pro 2 as well only when games actually loaded. I noticed on another forum a user mentioning the ASUS AI Suite 3 causing issues. I un-installed the AI Suite 3 utility, the Vive Console and Stream VR, rebooted, re-installed Vive software and SteamVR, and all was good.
I re-installed AI Suite 3 and sure enough the problems can back.