Overaggressive LLM scrapers have probably destroyed the feasibility of this idea, independently of whether the idea itself is any good. There are now captchas and other roadblocks in front of everything, which stop even tiny amounts of automation because of the sites getting hammered by the huge gobblers.

Part 3 itself would be the thing the gobblers are interested in though, right? THis Let Me Know thing can just hit a URL and get back a "yep, 200, its up" or a "nope, 204, not yet".