This is a tactic that worked for me, but your mileage may vary. I used to get dozens of spam calls a day on both my work and personal numbers. I did all the things that you’re supposed to do and they just kept coming. I also needed to answer unknown numbers on my work phone so I couldn’t just block them.
So after a while, I started answering the calls and calling them back when I got silence. I made sure I could talk to a person/scammer as often as possible. In the beginning I would just ask them if they felt good about themselves trying to scam people out of their money. They would generally just hang up but one guy gave this long speech about how if you were that dumb you didn’t deserve that much money and how he was living the American dream (although I did ask him if he was in American at which point he hung up on me). After that, I would just start trying to keep them on the phone as long as possible. My job is such that I can work and talk on the phone at the same time, so I made a word document that had a fake name, birth day, social security number, address, a fake person basically. Then I would put on my “old man” voice and just act stupid to keep them on the phone. I kept one guy on the phone for four hours as I pretended to be too inept to turn on my laptop to give him my IP address. He was quite upset when I told him I knew he was scamming me.
Anyway, I haven’t gotten a scam call in like 6 months. I think scammers put me on their do not call list. Maybe worth a shot?