@kmic @timorl shameless plug, .IS is pretty good too (disclaimer: I do information security for .IS). If you want to know how we do (some) things, here's the CTO talking:
https://server.vpnwp.com/proxmox/june-2021-freebsd-developer-summit-icelandic-dns-registry/

We do contribute to FLOSS, for example here's my work project:
https://gitlab.com/isnic/prober

If .IS is not your thing, https://njal.la might be what you're after. Created by Peter Sunde of The Pirate Bay fame, and pretty solid from what I've seen.