[otabdeveloper4]

> What are the viable alternatives to LE?

None. Big tech intentionally made Let's Encrypt a single point of giant failure.

> And in case none exists, what does it take to build one?

A new Internet and Web standards stack. The whole problem is self-imposed -- we could have published self-signed Ed25519 keys on the DNS instead, and the result would be more secure than whatever it is we have now.

[icedchai]

Do you remember the early days of SSL certificates? It took an act of god just to get a certificate: verification rituals like faxing corporate paper work, phone calls, manually reissuing certs because someone forgot the "www", forgotten renewals...

Let's Encrypt is incredible.