In the absence of serious kinetic compression, that ice is going to be harder than steel. And without something to provide outside energy to the planet, any subsurface ocean would have frozen long ago.
At least on Europa, you have the gigantic tidal forces generated by Jupiter to (theoretically) knead the moon’s core like play-doh, keeping it molten and providing energy (through marine volcanoes) to keep the water liquid and supplying minerals and other nutrients that could be taken advantage of by life.
Except we can’t go to Europa. Or at least if we do, folks will just get eaten by the glow-in-the-dark squids.