My 5G

If you're not seeing 5G on the display, I'm guessing that there there could be several reasons for it:

• You haven't paid for cellular service – or at least, not for cellular service from a carrier that supports 5G.
• You're in an area where your carrier has poor coverage for 5G.
• Something is broken in your iPhone and it needs hardware service.

My guess is that it is most likely to be a coverage issue – something you need to contact your phone company (carrier) about.

Then contact your carrier for help with their service.

If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support