AT&T Call Protect was doing wonders for me over the last couple of years but in the past couple of months things seem to have accelerated as they are consistently ringing through (usually political garbage OR a pretend car warranty expiration thing). Though it appears to have still blocked 40+ calls this year alone with several others ringing through with a spam notification on it. Just not in these past few months has it worked consistently.
Must garden until 2/1/2022 to hit my goal AAOA. 
I've tried RoboKiller, NoMoRobo, and the Verizon service (which was actually free for a period with our business account). None of them seemed to work well enough to continue to pay for. RoboKiller was kind of fun with the rare actual live caller as it will play prerecorded messages that sound like someone answered and keeps the caller tied up until they realize it's a recording and hang up. It records the conversation for you to play back.
My spam calls kind of come in waves. Debbie from Visa/MasterCard Account Services only calls me once or twice a day to let me know that there is currently no problem with my account but I have been approved for a lower rate. The IRS only calls once a week to request their Green Dot or Amazon gift cards to keep law enforcement agents from arresting me. Bank of America's Chinese headquarters only calls me about once a week. About six months ago, I was getting a dozen or more of these a day. 😒
The various services work using a database of known numbers, but since nearly all of them are spoofed numbers it doesn't really help that much. I do know that when I see a call with my 617 area code and the same prefix as my cell it's going to be spam using a spoofed "local" number. I guess that's still effective for people with land lines in small towns, but in most major cities that prefix is fairly random.
What's been most annoying lately is the number of SMS spam messages I have been getting. None of the services or iPhone's built-in version (which works on iMessages but not SMS) seem to help with those. I get 10-15 messages a day with offers for CBD, "enhancement" pills, weight loss pills, a reminder that I haven't claimed my Amazon or Walmart gift card, or FedEx or DHL asking me to call them to claim my parcel they have been unable to deliver. Since most of these include my first name, I am assuming they are related to one of the various data breeches.
Unfortunately, my phone is paid for by my employer and it's common for me to receive legitimate calls or texts from numbers not in my Contacts list that I have to answer, so do not disturb except for contacts is not an option for me.
