I configured my kid's tablet to use AdGuard's public DNS https://adguard-dns.io/en/public-dns.html

No more in-app ads.

Strange thing, I tried it on my FireTV to block youtube ads, but it didn't work. I wouldn't be surprised if the FireTV monkies around with user settings. The other explanation could be that youtube uses the same hostname for videos and ads, so the DNS blocking can't distinguish.

I ended up side-loading a 3rd party YT client that doesn't play ads. https://smartyoutubetv.github.io/

How much time did it take to research + install a Pi-hole?

I used a pi-hole, but wanted it to work outside my home as well. NextDNS uses many of the same blocklists, and I happily pay $20/year for it. Also has apps for devices that roam from the house.

https://nextdns.io/pricing

They try to make it super easy: https://pi-hole.net/ and I have no recollection of encountering any issues.

OTOH I am a software engineer working with Linux and network related stuff.

The issues comes later when some pages may break. When that happens you need to stop bashing your computer and add some URLs to the Pi-hole whitelist (or skip those parts of the web...). In my experience there has been few issues. Some enterprisey stuff my wife needed for work depended on some oracle tracking URLs that were blocked if I remember correctly.

Can you write exceptions for IPs within your network? I’d like to exclude our work laptops from filtering. Both laptops have static IPs on my network.

Reading more I could just change my devices dns settings to use what I want. A little more cumbersome and requires local admin on windows.

You can create IP based exceptions, or you can point those machines at another dns resolver. Either works.