No, I don't think it's related. I have only the vaguest ideas on metallurgy so take it with a pile of salt, though.

Maraging steel is a rather unusual alloy of iron, nickel and cobalt with other things in it (molybdenum, titanium, aluminium, silicon, copper ...) but no carbon (which is unusual for high-strength steel) with special heat treatment. But I haven't seen anywhere that manufacturing it requires a cold alloying. So I'd presume it uses normal alloying in liquid phase in a crucible.

The isostatic presses would rather be used for things like ceramics.