Apple iPhone 12 Pro Max Update 18.3.1 Blocked My Mobile Data and I Need a Fix

My Apple iPhone 12 Pro Max was automatically updated to version 18.3.1 last night. However, this morning, none of my apps open when using my mobile data. Only WhatsApp can send messages, and even that barely works. I cannot make video calls or access any other applications. It feels like my phone has been completely locked, and I cannot roll back the update. I tried restarting my phone and resetting network settings, but nothing changed. This is extremely frustrating, especially since I rely on mobile data for work and daily communication. Everything works fine when connected to Wi-Fi, but I am unable to use my mobile data at all. I urgently request the authorities to fix this issue as soon as possible.