Cellular Update Failed -- Help!

About two days ago, I first got a notification stating "Cellular Update Failed: Your iPhone cannot make and receive calls or access cellular data until it has been updated". I've done what Apple has wanted me to do: plug my phone into my computer and reinstall the software with iTunes. This worked for a few hours, but then it stopped. I then decided to take out my SIM card and put it back in. This worked for a while, and when restarting the phone wouldn't fix the problem, this would. Eventually this stopped working, which is when I tried to reinstall the software again, but that still doesn't work.

I'm thinking maybe it could be due to my SIM card being scratched, there are three lines on the card from the contacts within the phone. But I don't know because I feel like those lines shouldn't be impacting anything all of a sudden.

When I go to the about section of my phone, everything is shown except for "Modem Firmware", which is blank.

Any help would be appreciated. I have an iPhone 7 running iOS 13.3.