Infomaniak are good. Awful ux but good on other stuff.

You mean registrar. The registry is the place that administers the register of domains within a TLD (like .se or .mobi) and for some reason doesn't let you order domains unless you want to become a registrar first

I don't know which registry is the best but I can tell you about the worst. My registrar was also not amused by the mess that is AFNIC (twice now, concerning different domain names, and I don't have many domains so if I already had multiple problems...). They sit in Paris and operate the TLDs of former colonies

For registrars, I picked OVH because they're among the cheapest and their servers have been very reliable and fast across the months where I tested them before switching over. Their software is ass though, the forms frequently display three languages due to broken translations (their source language is French, my contract language is Dutch so a lot of elements are in Dutch, and then English trickles through where I guess they have a translation available but not to Dutch), multi-year ordering broke at some point and hasn't gotten fixed, automatic renewal is wonky to set up... but once it runs, it simply works well so I still recommend it for people who want good service on a budget. You can also set records by editing the zone file which I appreciate. I've had registrars before that wouldn't let you use certain record types; don't have such problems here

I found .UK and .US domains cheap, but .UK was more private as far as whois goes.

https://njal.la/

Run by Gottfrid Svartholm Warg of The Pirate Bay who has already served two prison sentences for acting on his beliefs around personal freedom and intellectual property.

I have no idea about their privacy policy, but I've had great service and very cheap rates from Porkbun

You want privacy or cheap? Can't have both.

njal.la, but not cheap

Alibaba, They're so far away and big that no one can touch them.

.internal

Cheap and good: Cloudflare (they sell domains at cost, you won't find anywhere cheaper unless they're loss-leading) Currently the best choice, imo. API is useful for DNS01 Letsencrypt certs, with plugins for lots of software. Only downside is you can't use a third party nameserver without paying extra, but I've never found that necessary.

Ok and good: I've been pleased with Gandi and Joker in the past. Both are also not-US based, if that's important to you.

Privacy: Not sure what's exposed with a domain registrar. You have to give an owner's detail for any domain, but that's hidden from public whois now.

If you mean untraceable - well, I dunno. You don't need to prove that identity for anything other that .gov type domains, afaik, so I guess disposable email (but not that disposable, as lose that and you lose the domain) and pay by crypto.

Shitlist: GoDaddy for all the well published reasons. Had some problems with Fastnet in the past too. In both cases I was able to transfer domains away successfully.

(Experience: Personal. I've been registering, transferring and working with domains for over 20 years. Not full time, nor at huge scale.)

.Namecheap.com