If you are on Android 11 and travel outside France or Switzerland, you shouldn’t receive the update.
If you are on Android 12 and travel to France or Switzerland, you shouldn’t notice any difference in performance.
I checked, and I’m not able to share the names of the operators that will receive the A12 upgrade later. The same goes for the reason for the delay. All I can say is that it’s not related to the quality or coverage of the network itself, but rather the network-specific optimizations and features that we include with each software update.
Worry not, our team is working hard to deliver the upgrade to everyone and with some luck, it will be out before the end of March.