Subspace increases each time the navigation map resets during a drone exploration! The subspace does update correctly, but does not update.
This will be fixed after the 1-BIT Jam voting period ends!
"The subspace does update correctly, but does not update." - you mean the underlying value updates but the displayed value doesn't? I'm stuck here too.
If you need to get to 100 resets during a single drone deployment, that doesn't sound even remotely feasible. I don't think I've ever made it beyond 2, even with a T1 charge modifier.