Very true.

From the perspective of something like a Tardigrade we are definitely well into a “singularity”.

From the perspective of a rock the Tardigrade itself is matter experiencing a “singularity”.

Hmmm, when I studied GR, the consensus was that it came out of nowhere and if it wasn't for Einstein's genius, it would have taken at least a long time until someone else had discovered it. But you make a good point. Ultimately it's an unanswerable question, I guess.

Of all the physical theories, general relativity is probably the one that's least likely to be true of. Because it just wasn't needed in all its generality at that point of time. Instead of going from first principles like Einstein some other physicist could have developed it from the other end, and made corrections to Newton mechanics based on the observed precession of Mercury and the deflection of starlight by the Sun (if someone would have done that observation without the impetus of GR). It could have been akin to how quantum theory in its first 25 years was a collection of ad-hoc explanations of various phenomena using the quantized energy idea but having no generalized theory of them.

David Hilbert, for one, was apparently close. That said, I feel that it is a bit of a stretch to call it obvious (maybe more obvious in the sense of "this is the way to go" rather than that the answer was obvious.)