It entirely depends on which blocklist(s) you use. I had to stop using the StevenBlack list because it started breaking a lot of things, apparently intentionally.

I recommend using only one list, rather than a combination of several. I switched to the https://oisd.nl Big List, which has been great... although it did break GitHub yesterday. That was the first breakage since I switched, and it was fixed when I reported. But still, keeping an eye on it.

Hagezi blocklists are the current standard now: https://github.com/hagezi/dns-blocklists

You could go for one of the Lite blocklists for the network wide, family friendly (non-breaking) list.

OISD is what I use as well. It's great, the family don't have any issues like we used to with the other lists I used. It doesn't block as much, but I'll take the odd thing slipping through vs not being able to load a page we need.

I use PiHole, it does break some stuff here and there, and sometimes useful things like Private Relay or iCloud in iOS; or once YouTube history stopped working for me (apparently they use a separate domain to track watched videos and progress!). It also depends on the block lists you upload. It’s pretty easy to unblock, especially web, as you just look on which domain cannot resolve in the browser dev tools and add it to the allow list.

Yet, DNS-based blockers have a limited usefulness at this moment as some major ad-providers started using the same primary domain for serving ads. For example, YouTube, partially Google, Yandex. I guess they cover everything with top level load-balancer and then route internally to specific service ingresses

Sites break often if they're shitty. Especially if you click Google's "Sponsored" link by accident after a search because I block Google's ad stuff.

But, you get used to what sites break and decide if it is worth bothering to fix it or not.

I can disable my pihole by opening a browser, navigating to pihole and disabling it.

Affiliate links break, which can be annoying for other members of the household who may want them to work.

I use AdGuard home as part of my HomeAssistant setup and have had no problem at all. Only thing is to turn off the enforced safe search as that quite reduces results.

Forget about streaming media from amazon prime and various terrestrial broadcast apps. But just create 2 networks, one protected, one not.

rarely breaks. Also simple regex blocking goes a long way: .ads. will get rid of most ads domains. .tele. for telemetry etc