How can I block my missing iPhone 13?

Did you not have Find My turned on? If not there is nothing you can do about tracking it. No one can access your phone with it having a Passcode.

If it was turned on, but shows that it is not Available, there is still a chance it will come back online if another iPhone comes within Bluetooth range as long as the Battery has not run out. Review the Support Article here for other options including contacting your Cell Provider and reporting to the Police. While you may be able to remotely erase your phone, I would not remove it from your Account. That would be the last resort when you have given up and would allow any other person to set it up as their own device. Your data would be wiped.

If your iPhone or iPad was stolen - Apple Support

If you mark it as lost in Find My and provide a Contact Number, be aware that thieves can use the number to contact you claiming to be from Apple and asking for your Apple Account/Password or Passcode to unlock your phone. Do not fall for that.

It’s “blocked” from use by your passcode.

Thieves normally do take measures to avoid being tracked.

As long as the criminals don’t know the passcode, the data on the phone is VERY well protected.

As for your next steps, see:

If your iPhone or iPad was stolen - Apple Support