Spam messages and calls

You might find this useful:

Detect and block spam phone calls - Apple Support

It explains what options you have on the phone side of things.

You might also want to hear with your carrier if there is anything they can help you with.

Good luck!

There isn't much you can do. We all get spam. There are several Ad Blockers in the App Store that might help. Also be careful about giving out your phone number unless it is required.