Why Germany is racing to rebuild its army

Soldiers are useful things to have around when there are external threats. Yeah, they're also useful when you wish to BE an external threat, but others are filling those roles at the moment. Europe would be a different, probably more secure place, if the larger countries stood up a new mech infantry division while the smaller countries stood up a support or mech infantry brigade. Shared weapon technology, Europe-made, heavy use of man-portable and drone weapons. Let the external threats have the massive investments in tanks and ships while the putative battleground try to arm for a more modern defence.

And ships are difficult to apply to the European land mass, aside from convoy protection or mobile airfields or missile platforms. Mobility, though, tends to come with lower load outs.