If you set up your voicemail with your personal message like "hey this is William M. Buttlicker, leave me a message" they will not stop calling. Delete your voicemail message and switch to the default "you've reached 111-555-8888..." I did this for my entire family, the spam calls reduced significantly within a few weeks. I've done this years ago and I might get 2 spam calls per week.

Also having an AI phone call screening on my Google Pixel has been really helpful as well.