• AdGaurd and NextDNS are DNS providers. Your phone would send DNS queries to those sites and respond with the IP to use. They have built in blocklists you can use, which can be used to block ads and known malicious sites and such.
    TrackerControl is an application you can install, that monitors HTTP requests that apps make by using the Android VPN slot. It tries to categorize them and allow and block them, and you can customize what’s allowed and blocks.
    It looks like ReThink is a combination of the two, it seems to provide a cloud DNS service like NextDNS and AdGuard with a partner application that’s like TrackerControl.

    I use a combination of NextDNS and TrackerControl. NextDNS blocks most of my DNS requests, and TrackerControl covers anything else that’s missed by aggressively blocking by default.