Linux Mint is quite popular amongst beginners. But the main thing I want to say is: I recommend you to try the KDE desktop if you’re used to MS Windows. It has a tray, start menu, icons, scortcuts and everything. And it looks kind of familiar to Windows users.
Blocky is another nice AdBlocker and DNS proxy. I’ve been using it for quite a while. Seems to be pretty efficient, too. If you’re looking at community DNS servers, have a look at https://opennic.org/ that’s a democratic DNS root.
And by the way, take care not to expose your DNS server to the public internet, or some people will start using it for DNS amplification attacks. But that shouldn’t be any concern if you run it on a Raspberry Pi at home.