There's also vanity DNS for business and enterprise plans - but AFAIU that's basically just slapping another name on cloudflare DNS - not ability to point ns records to non-cf servers?
I have had a good experience with Cloudflare's registry service over the last couple of years.
I have taken to gradually pushing my registrations out as far as they can go. I just occasionally add years onto domains I buy, so as to lock in the $9 price for that term. Seems like an excellent way to avoid inflationary price increases, or general pricing creep.
Are you saying that it's not possible to use your own nameservers for domains purchased through Cloudflare?