Since previous update I've had no mobile network coverage and then another update now phone seems take longer to charge and still no network have lost work and all sorts of problems not happy considering the phones is meant to be 1.600 £ I've got Sony Ericsson at moment full signal so old it's small pics plastic charger connection etc fantastic more reliable than an apparent 1.700 £ phone wellmdone Samsung
You arent the first to experience this. People have been experiencing this issue on their s21 ultra since the July security update and its still not been fixed. Do you have a 🚫 sign showing in the signal area? Can you post a screenshot?