For anyone running OpenWRT, you can install the adblock package to accomplish roughly the same thing as Pi-hole does. I don't believe it supports some advanced features like DoH/DoT or DNS resolution (e.g. a1b2c3.example.com -> ad-server-that-should-be-blocked.com), but it does the basics - custom host file sources, additional blacklist rules, whitelisting, and quick enable/disable for troubleshooting.
It also has an option to force all DNS traffic (port 53, so again it won't catch DoH/DoT) to go through the router. Occasionally I forget I've done this and tried `dig foo.bar @1.1.1.1` and gotten confused until I remember that my router is forcing that DNS lookup to go through it first, and then through the router's configured DNS resolver.
It also has an option to force all DNS traffic (port 53, so again it won't catch DoH/DoT) to go through the router. Occasionally I forget I've done this and tried `dig foo.bar @1.1.1.1` and gotten confused until I remember that my router is forcing that DNS lookup to go through it first, and then through the router's configured DNS resolver.