i switched from pihole to adguard because adguard is bsd compatible and runs on my opnsense router. for linux, the main benefit of adguard is that it is a self-contained app-image. pihole is a bit of a mess of packages that it installs (if installing on pc rather than a pi) , rather than being part of a distribution’s native ports. upgrading adguard is also trivial.
This is The Way