My OpenWRT uses in-memory blacklist in dnsmasq on Omnia Turris that's faster than rpi.

I would imagine the performance of settings it on pihole would be unnoticeable, as it also stores blacklist in memory. The only latency difference would be in network request likely.

Also on Turris with knot-resolver and adblock... is there a reason to outsource blocking really? Why trust nextdns? Isn’t going to be a subscription based service once out of beta?

Some reasons can be: easier to setup, can be used on devices when on the go, get encryption by default with DoH.

Most routers are not powerful enough to efficiently run blocklists and analytics locally.

I can’t speak to the comparison but as someone who was skeptical of the pihole-on-rpi setup I am now a believer. I can’t live without it now.

I should definitely do some benchmarks though. There are occasional times where I feel like DNS lookups take significantly longer than normal but that’s once in a blue moon.

Same. Although I did end up migrating to a DO droplet so I could use it outside of home and share with family/friends. Absolutely can't live without it now.