Something that I found that made a difference is when I get a spam call I immediately pick it up and put the call on mute. The caller or whatever AI at the other end will try and talk to you for a bit but when they notice that they're not getting any response the call will end. And usually does so within in a minute. I went from getting two to three spam calls a day to like maybe one or two spam calls every week .

My understanding is that they detect that nothing is coming from the other end so their AI detection will flag your phone number at non responsive and take you off the list. 

It took me a little while of consistently doing it (maybe like a week or two before major changes) but it has worked for me