How to stop spam texts from email addresses

I’m getting texts to my mobile number as part of a block of 20 numbers total, from constantly changing email accounts. I have turned off alerts and blocked the address each time, but it is useless as there is always a new address. They are inappropriate sex spam messages. I have received a death threat text immediately after that likely came from a misunderstanding fellow victim. This is happening about 3-5 times a week up to multiple times a day to the point that I cannot allow my son to see my phone. Is it possible to turn off receiving texts from email accounts? I don’t think I’ve ever received a legitimate text message from an email address. I am considering changing my phone number at this point.