I am using it. Activated few days ago on tmo version (HD1907). Prior to that it was converted to international fw 10.0.16.HD65AA.
Everything seems to work except:
1) I have option to enable Wi-Fi calling in Google FI app, it is enabled. If I turn phone into the plane mode and enable Wi-Fi it doesn't allow me to call saying I have to disable airplane mode. This used to work on Pixel. So I cannot tell it VoWiFi works or not, maybe yes maybe not, you will never tell unless check your billing and/or be in an area where you only have Wi-Fi and maybe roaming. I wasn't.
2) I am unable to switch network to Sprint, even though it shall be formally merged with TMO by now. Signal Spy just cannot do it. That said, it used to do it on Pixel couple years ago, but stopped working even on Pixel. So I am uncertain if that is a body or merger issue. Yet have to be in an area where only Sprint or US Cellular towers are present, but this will hardly happen.
3) FI specific google VPN does not work (this is for a good in my book).
Visual voicemail works with OOS phone app.
I can install google dealer without Magisk module, so that module is not needed on this FW. I don't see any benefits to use it though, except if I would like to use Google's call screening and spam protection. I am using a 3rd party dealer anyway with its own features like that pre-existed Google's implementation. I.e. if that is an issue, that issue can be solved by a 3rd party SW, you are not bound to Google here. But you can install their dealer on global FW if you so want.
Other than that everything seems to work. I'd like to see what happens in roaming but I don't expect problems there. It would be a very strange idea to prohibit roaming based on the IMEI. Anyhow, there is no way to check during the times of closed borders.
I didn't install a second SIM yet though.