iPhone 12; cellular gave hardware error, but now working again?

Hello,

So about a week ago the cellular stopped working on my iPhone. There wasn't even an IMEI output when dialing *#06#. I did the Apple Support check and it said there was a hardware issue. After some googling it seemed like a basebrand issue and I checked some local repair shops who quoted me on the repair.

I tried reseting the phone a few times and then also tried the DFU restore but nothing helped.

I erased the phone and put it up for sale noting the defective cellular service.

THEN, yesterday after ordering an Android phone as a replacement I dug the iphone out of the closet and restored my last backup from my Mac since I wanted to use the Switch to Android app to move my apps and such.

The cellular is working again...

I have used it since yesterday and it is still working. I can also get the imei again using *#06#

Does this mean it was a software issue? If it really was a hardware can leaving it sit really fix it?

I want to keep using it but I also don't want to be stuck without cellular while out on a trip or something.

Thank you for any advice or maybe stories of this happening to somebody else.