Locked Screen Spam Messages

For over a year I have been getting spam messages come through over my locked screen - completely overriding my settings. They have to be accepted or dismissed before I can unlock my phone. It is also very easy to accidentally accept these full screen prompts - which would have you paying money every month for whatever spam they’re trying to sell.

I have “opted out” of these messages COUNTLESS times yet I still receive them. I have no idea how this is even legal to be able to spam a customer like this.

What is even more frustrating is these messages alert on my watch too and continue buzzing till I’ve dismissed it on my Lock Screen. Which is wildly frustrating if I am busy with a task and not near my phone.

How do I stop these messages?! I’m ready to do a sim swap to another provider.