I have a fire tv and run adguard, which does the same thing as pihole, and I can barely tell it's on. It may block some tracking, but I get an increasing amount of ads in the fire tv GUI, not to speak of YouTube ads.

Sometimes I wonder if the people recommending pihole actually tried it. You get much better value out of ublock, smarttube, and so on.

This is a great suggestion. I've run two on my local network for about five years:

pi#1) My personal DNS resolver, which I manually configure on each device.

pi#2) The much less restrictive DNS resolver which my DHCP server automatically issues to all other network clients, including all phones and IoT [0]

Individual hosts can then manually configure their DNS to resolve to the local network router (or third-party DNS), which effectively bypasses both PiHoles (for that device, only).

[0] There is a method to use a firewall to capture all outbound DNS and force routing through PiHole (ifsense? I don't know), which may be necessary for hard-coded DNS-IPs. I do not know how to do this but it's not necessary on my network.

Often devices will have the DNS server hard-coded and never connect to the pihole DNS server. This is not just to avoid ad-blocking but to make the DNS more reliable and avoiding having lots of potential support issues around faulty DNS.