Is my iPhone 12 SIM card reader broken?

I bought an iPhone 12 Pro Max in Algeria and then bought a SIM card for it from an Algerian company and everything worked fine I then moved to Canada and I switched my provider to fidoo in Quebec and it worked great until I left Quebec to Ontario and then Calgary the SIM card stopped working so I went to Fidoo and switched my SIM card and it still didn’t work so I switched to multiple providers and none worked it just kept saying no service after I put a SIM card in so I tried my SIM card on a different phone and it worked fine so the SIM card works like normal it’s just the phone that doesn’t work and keeps saying no service so I took it to apple and they said they tried everything they could to fix it but they weren’t able to. The phone is not carrier locker because it says no sim restrictions however I’ve discovered that if I go to setting > general > about and scroll to physical sim network it says phone not allowed but the phone also says no sim restrictions so I’m confused I’ve tried everything like resetting the phone turning airplane mode off and on nothing works even apple said they tried everything so now I don’t know what to do with the phone

[Re-Titled by Moderator]