Thank you a lot!
In the meanwhile I discovered on alternativesTo the app Blokada.
I didn't understand well the functioning... it says it uses a VPN. I don't know why... I it says it uses a DNS filter... how? And futhermore it seems to use an hosts file, but I already tried AdAway and it seems to not work very well.
Anyway it's popular, so I installed it. I'll try and see.
My Main goal, I must admit, is Spotify. I mean, I was ready to pass to premium, but 10 bucks at month seems to me a bit too much, greedy devs