Adguard Home Support
Would you be able to add support for AdGuard Home? AdGuard Home is an alternative to Pi-Hole and it supports Adblock syntax in addition to hosts & domain syntax.
The advantage of adblock syntax is that it would cover subdomains as well. It should be relatively straight forward to add support using existing domains list by prefixing it with || and postfixing with ^. It would look something like this
||example.com^
Information regarding Adguard Home syntax support https://github.com/adguardteam/adguardhome/wiki/Hosts-Blocklists