I have now:
* installed the latest TWRP
* flashed the updated ROM
* installed the latest Magisk via TWRP
* turned on Zygisk and Denylist
* installed the latest Play Integrity Fix module
* cleared files/cache from all the Google apps I could find (Games, Store, Wallet and Services)
* installed SPIC and gotten:
* PLAY_RECOGNIZED as Play Integrity Result
* MEETS_DEVICE_INTEGRITY as Device recognition verdict
* Evaluation Type BASIC
* Basic Integrity passed
* CTS Profile Match passed
All is still not well:
* Every 2 minutes a window pops up with an error message "Intent Filter Verification Servic...", disrupting whatever I am doing with my phone (pic attached)
* I can not download Netflix from the Play Store since my device is not supported (just a test to see if the integrity holds up)
On the positive side:
* my bank app works
* Google Wallet is no longer saying that NFC payments aren't working (although have not been able to test it since it's late here)
Not happy about all this at all, but we will see. At least I'm learning a lot about flashing things. Guess my anger at Google is giving me something positive back.