Certainly the buggiest update I've experienced in 17 years of Mac ownership - Sidecar connects to iPad, but only shows a black screen, Apple ID constantly asking me to log in, something gone very wrong with bluetooth where it randomly disconnects all devices but also causes warbling audio issues (a significant issues when running webinars for work), and its also borked webex screen/app sharing (webex insists their app is up to date and compaitble, so issue is on my side).
All in all, really wish I'd waited, some pretty major issues for me (although mail, music etc etc are all fine

)