iOS 14.6 update disabled cellular data

I have the same problem with my iPhone 12 Pro Max. I reached out to TMobile customer service and got a new SIM card. I am able to get cellular data with the same SIM card on my old iPhone Xs Max on iOS 14.4, but not the 12 Pro Max on iOS 14.6. There's no way for me to roll back to the iOS 14.5 even though I reset it to the factory setting; the 12 Pro Max stays on iOS 14.6.

This bug needs to be fixed ASAP!!!

I am having similar problem since updating my iPhone X to 14.6 on 7 June but mine is with WiFi. Phone settings show that WiFi is linked to correct network, but no WiFi symbol appears and unable to access many of my apps. Have an old iPhone 5 which I recharged and it is accessing the WiFi network. Spent nearly two hours talking to my service provider trying all sorts of solutions as I initially thought it was a provider error until I backtracked my usage. I've never had a problem before with updates and, sadly, I'm not 'tech savvy' so a lot of the time I'm out of my depth. Hopefully something sorted soon.

This is horrible. I cannot use my map service when I am driving looking for direction. I cannot use my mobile boarding pass when I am in the airport. This release is not well tested. It's hard to believe Apple releases this update without testing well!

My WiFi problem has been fixed after a second visit to internet provider. The VPN in Settings was flickering and when opened showed Ad Block. She checked this out and advised that the Ad Block could be causing the problem, so deleted this and WiFi was restored. I did downloaded the Ad Block ages ago but it had never caused a problem before when downloading updates, so I still do think that the IOS 14.6 update had something to do with it.