RingCentral had some really nice features; we used it for our business several years ago and I had considered using it as a virtual clearing house for my family to help keep our personal numbers private when signing up for things.
I had even ported a Google Voice number to RingCentral well before that process was streamlined.
I used PiHole for a long time, then graduated to self-hosting a VPN so I could get as-blocking when away from my home network.
Ultimately I ended up using just AdGuard DNS via the DNS profile for iOS, and hard code the DNS into my home routers.
There might be a better setup, but this simple deployment takes care of 98% of ads.