No Sim detected..iPhone 12

Everything was fine and suddenly, there was no line.

Airplane mode on/off..still the same

Removed sim card and reinsert..nothing changes

Tried my sim on friend's phone, no issue

Put friend's sim on my phone, no sim detected

Reset network

Restore iphone

Hard reset iphone

Check if there's new firmware..none..phone is fully updated

Still no sim detected..out of a sudden

Wifi is working..

Phone just pass through 1 year mark..sooo..no warranty? Perfect!

so, how do I rectify this?