Can I use a new 5g sim card in my iPhone xr?

I got an iPhone xr from my grandma that she hadn't used in a while and it was ready for me to set up and use. The sim card reader itself ended up being bad, and the apple genius bar couldn't fix it. I ordered a new sim reader from ifixit, and installed it myself. It doesn't pick up any signal when I insert my 5g sim card. I know it's a good reader because it worked when installed in my old xr with a broken screen. Any ideas as to why it won't let me use it? I can't get past setup without an update that's wants the sim card and tray functional.