I need to know why my iPhone says carrier iPhone 54.0

The Carrier settings version indicates the specific set of cellular settings that are loaded on your iPhone, which is being determined by your Cellular Provider. Unless you are debugging an issue with your cellular connection, you shouldn't really care about that number; it's just a software version.

Now, onto your SIM locked issue. Don't try to guess your SIM PIN. The wrong guess can permanently lock your SIM card, which means that you would need a new SIM card.

• Contact the carrier that gave you the SIM card. If you aren't sure which carrier to call, remove your iPhone SIM card or iPad SIM card and check the card for the carrier's name or logo.

• Ask your carrier to help you unlock your SIM card using the default SIM PIN or PUK code. 
• If you can't unlock your SIM card using the SIM PIN or PUK code or if an alert says, "PUK exhausted," ask for a new SIM card.

See Use a SIM PIN for your iPhone or iPad - Apple Support for more information.

But what about esim they are not physically removable how would we know what carrier it is then?

You told us that this is your phone. Surely you know who your carrier is. You pay them for cellular service every month.

Hopefully, you did not recently buy a SIM locked phone from someone. If you did, you will have to ask them who the carrier might be for the phone.

Did you buy this phone used? Otherwise it seems odd not to know who the carrier is or ask whoever actually pays the phone bill this. Ultimately the phone sounds like it is carrier locked. Even if you found out the carrier if it wasn’t your account the carrier is unlikely to be willing to unlock it for you. You need to have the original owner do it.