I got the update a week ago. I didn’t reset anything after. With the exception of the removed (by Google) workaround for 5GHz WiFi problems it’s been 100% hassle-free for me. Even better, it has solved a long-standing Bluetooth problem where Bluetooth would be off after a reboot or plane mode and would refuse to turn on several times. It just works now. Also, my impression is that battery life is a bit better than with Android 10.
On the more negative side, they seem to have given up on lowering the minimum screen brightness. After the botched attempt and revert last August @formerFP.Com.Manager wrote that they’d re-introduce it soon, but that plan seems to now share the fate of the camera software improvements that were supposedly just around the corner back in September 2020.
Regarding WiFi, I had the expected disconnects as soon as my FritzBox selected a channel of 106 or above – with which none of the 9 non-Fairphone devices using 5GHz WiFi in our house ever had any issue. I’ve now fixed my FritzBox to channel 52 and will just have to live with unstable WiFi when I’m connected to someone else’s FritzBox. Oh well.