Submersible Pump Depth Ratings

Hello, has anyone tested the depth limits of a traditional submersible water pump like this one:

Based on ripping one apart, it looks like the motor coils are potted in epoxy including the power cable. Since pressure will be equalized internally and externally at depth within the pump, I am wondering what depth I could operate this pump before it were to implode. I wouldn’t be trying to pump water back to the surface, just move water around at depth, so no delta p between intake and exhaust. Has anybody tested the depth limits of one of these pumps?

Thanks!

Ethan