I'd appreciate some advice on what I can use to fill fine, deep cracks
in my 1-1/2" gypcrete floor to stop it from making crunching sounds
when I walk on it.

I suspect that I'd need a liquid that's thin enough to penetrate the
cracks to full depth and then harden within a short time. Since water
isn't compatible with gypcrete, the filler couldn't be water-based.

Thanks in advance for your helpful replies.