I actively looked for someone we could pay money to, so we are their customer (as opposed to being a free tier user, effectively a cost)
The winner was DNSimple[1], who do exactly 1 thing, and they do it extremely well. And they are small enough to not take themselves too seriously[2], which I really appreciate.
Oh and their normal support channel is email, and everyone in the company takes a turn. I tested out their support before signing up and quickly heard back from a competent engineer, so they passed that test too.
[1] https://dnsimple.com [2] https://dnsimple.com/dnsound <— bonkers