Also the App could trivially bypass your local DNS and use its own. Even if you blocked port 53 in an attempt to prevent this it would be useless if the app used DNS over HTTPS.
I love PiHole for ad blocking, but against this it is ineffective.
I consider Connections to be one of the best things ever put on television and still rewatch it periodically. I am off to hunt down the new one right now.
I was using Proton Free for the last year and they are great but am currently giving Surfshark a try since they had an even cheaper deal going on recently. So far so good.
10 years ago I was working at a place that still used an Apple ][e
It controlled a ROM burner that was vital to the manufacturing process. In a back room was a stack of backup ][e s just in case the production one should ever fail. In the years I worked there it never did.