I'm assuming once that site got even remotely popular, it would be smacked with a cease & desist

But that's just the pessimist in me complaining about bigCo.

Sites exist like "CanIStreamIt?" for years and haven't been shut down by Netflix/Amazon, so maybe there's a legal way to go about it?

Why would they get hit with a C&D? What are they doing wrong?

Bare facts have no protection. Netflix owns Squid Game's media content, but they have no ownership over "Netflix has a program called Squid Game that is currently available." or "As of blahblah date Netflix will no longer have Squid Game available in CountryX."

Are we reinventing web rings and directories? I don't mind, those were fun!

> If their search is indeed not good, then I see a great opportunity in creating custom search filters, as a community.

It's not, but creating good custom search filters is a lot of effort, and not easy to monetize.