Yes! I have a split DNS setup with technitium using advanced forwarding plugin. You can set different upstream based on client IP or subnet. So this way you can send to vpn DNS to prevent leaking.

Also you can have multiple piholes (poor mans setup) and have each configured filtering for dedicated VLAN. For instance be more strict for guest kids and less on adults net. Adguard can do that without having to have many instances but then Adguard can’t forward traffic based on origin IP. You can make any kind of logic and send different clients to different upstreams. As far as I know only BIND provides this functionality through views but it’s more complicated setup and no lovely GUI. You can always send all traffic through tunnel but then some results may be not ideal if you will be detected to be in different country and content will be served in other language. I think results will vary based on VPN endpoint. You don’t need to tunnel through vpn if you use DNS over https. It’s completely invisible to the ISP. VPN is more of a use case if you want to be consistent with your exit IP and DNS queries.