Iphone 11 pro max updates to ios 14.3 and nothing change except modem firmware and carrier changed. it’s so disappointing from apple after stop production of 11 pro😔 what should we do?

ios 14.3 beta 2 changed sim operator delete vpn (toggle on and off) none of them doesn’t help whats going on? what should we do? we have an unusable iphone now thanks to Apple

it takes for me just 10 minutes to get down the anten bar to no service after update the ios 14.1 to 14.2,,,it's so bad a new ios makes my iphone 11 pro max an unsable phone. i don't know why even if it's no service battery drain down with network coverage. i do 1.hard resetsoft reset reset network settings remove sim when off and get in when it's on air plane mode turn on and off restore to ios 14.2 downgrade to 14.1 that was no problem with 14.1 but it's still there how long it will be there i don't know but it makes me crazy