Usually I will donate to an app developer (for example, I use Keepass2Android and the developer has a separate app that takes donations as an in-app purchase). Alternatively, you can use your credit towards a monthly Google One subscription.

Thanks for the explicit mention, I should have been less vague with my "planning the security aspects" comment. I was thinking firewall rules would mitigate that, but could moot if the friends are on a dynamic lease.

VPN is a bit of a non starter since that would require installing and running a VPN client 24/7 on all devices, else you're dropping in a site to site VPN device on the network... At that point you might as well cut out the extra complication and just run PiHole on that point.

I actually learned about public AdGuard servers in this thread! I'd definitely lean that way if I were OP (because I personally do not want to field "the internet is not working" calls in the middle of the night).

Depending on what pods they use, you could also look into "fancy" pods - Colonna has a Gesha pod (https://colonnacoffee.com/...). No idea personally if it's any good, though I have the pods here myself but the wrong machine 😅

Is there a backend component to it? I thought it was strictly a frontend client interacting directly with the Lemmy API; therefore all the errors were coming from the lemmy.world instance... If that isn't the case then I'll maybe spend the time to spin up a wefwef deployment myself too.

Spitballing ideas:

• Run PiHole on a public facing server/port. You'll probably need to plan out the security aspects of it, but then your friends could then just set their devices to use the PiHole DNS (much like how people can set their devices to use 1.1.1.1 or 8.8.8.8).
• Drop a Pi with PiHole in their network that is managed with some fleet/IOT management platform like Balena. That'll in theory get you PiHole running in a container, and you'll have a management platform to actually remotely connect to the Pi to manage it.

You may be already aware, but be mindful of the danger associated with having an ounce of responsibility for their DNS uptime. The bonus of option #1 is that you could also empower your friends to "bypass" PiHole should it go belly up.

Edit: Don't do #1 unless you can properly secure it.