A "Let's Encrypt" style org for a 3 letter TLD would be interesting. And it doesn't even have to be in the "completely free" sense, just an industry backed org interested in providing a well managed TLD without an interest in making a profit from doing so.

I know there were places like tk but they were less an organization managing the TLD and more a phishing and SPAM pit which still had a paid side of the business anyways. Other places offer varying things on this spectrum for subdomains but it's not a TLD and they often don't attempt to solve any of the actual problems offering domains does.

An alternative root just feels excessive given we only need 1 "good natured" TLD for the way we use the web to remain unchanged while preventing price gouging to host on it.