I can confirm that my Android fully updated[1] to Android 11 Xperia 10 II was fine to flash with SFOS 4.1 :-)

So far I noticed 2 minor issue inside SFOS, but I doubt they are related to mine being on latest Sony offered Android 11 before starting to flash 4.1

1. in addition to the documented loss of WLAN password on first reboot of SFOS, I also had to re-learn the fingerprints I had set up (when the initial bringup app on SFOS suggested I do so).

2. closing/opening the cover of the 15€ case it is in does not lead to screen sleep/wake. I forgot to actively test that under Android, doh! But it is most probably the case's fault because if I remove the 10 II from the case and pass the cover over the screen in search of the magnet and sensor, there is a point where SFOS will sleep/wake the screen just fine (not knowing where the 10 II has the sensor, I'm unsure which of the case's magnets triggers it)


pcfe
[1] the 10 II actually offered me two Android updates in a row when I took it into use late last week (2021-05-27 or -28). I applied one after the other, did all the steps under Test key functions of your Xperia 10 running Android and it's been an eventless flashing of SFOS.