iPhone 12's WiFi and Bluetooth malfunctioning

So I’ve recently had problems with my phone (IPhone 12) crashing and then my WiFi being greyed out and my Bluetooth considered „unavailable“. Ive done countless things like updating my Phone to IOS 16.5.1, resetting all settings multiple times or even resetting my phone entirely. Funnily some of these things made it work again for a good 5 minutes before the same thing happened, crash, gone. I took my phone to two repair stores, with the first one telling me they can’t do anything about it and the second one agreeing to repair it. That made it work for 25 minutes at the price of 200 dollars. So now I tried to fully restore my phone in DFU mode and installing a completely new IPSW but that didn’t even give me 5 minutes of time, it did nothing. So now I basically got scammed of my money and still don’t know my problem, it says N/A when I want to see my WiFi address but the Bluetooth and Modem information is there. I really don’t now what to do

[Re-Titled by Moderator]