4G signal stopping after a week or so
After smashing and replacing the screen on my iPhone 8 Plus, the mobile signal isn't working properly. 3G and 4G, different providers (all the same network though), different SIM cards, and a new antenna (wifi diversity) cable but still the problem persists. The SIM will work perfectly on an iPhone 5S. I've also done a FDU restore on my phone also.
I'll get signal back for some amount of time (a few minutes to a few weeks) if I turn the phone off then back on, put airplane mode on for a minute then off again, or even if I let it sit without a sim for a while, then put one in. After a while it'll switch between SOS only and No Service.
Thank you all for your help.