If you go Android, definitely take a look at userspace firewall options. I like and use NetGuard, it's open source, and all done through the local VPN API (no t

If you go Android, definitely take a look at userspace firewall options. I like and use NetGuard, it's open source, and all done through the local VPN API (no traffic leaves device) - gives you control of which apps can go online. If you install it from GitHub (rather than the play store, no root required either way), it can do local DNS host blocking too.