Does it puddle in the lowest spot? Could you have it jack hammered up in that spot and install a sump and put a sump pump in it then have that piped straight up through a check valve and send the pipe out the side of the garage then down and out to wherever you want to discharge it? If the low spot is smack in the middle of a parking space that would obviously eliminate that space but it would be better than the garage flooding.Often enough since 1999 that I have tried all the tricks and tips, including a few thing I've done to help avoid it.
Biggest problem is drain(circa 1976) doesn't work well, tried to snake it but not long enough, supposed dry well is probably saturated. I don't really know the details of how the drain system was constructed. I do know the entire floor is not properly sloped to drain.
Have a squeegee, it works OK, not great.
Have a pump I can hook up, but it's kind of a PITA to set up and keep it primed. Using it depends on how deep the flood is.
Either way the shop vac still needed to get in the low spots around edge of garage,
it's not hard to push it to the garage entrance apron(1" lower than floor) to drain.