Essentially all heavy equipment is either used in international missions, needed for training or is not fully operational. I don't think that for example
@Rajma in Lithuania would be very happy if the Bundeswehr has to withdraw from the NATO enhanced forward presence mission, because we give our tanks to Ukraine.
It's terrible that we have to think about such choices, and it makes us look both weak and stupid (rightfully so), but if I had to decide between throwing a NATO and EU member under the bus, or some random country we have no close ties or formal alliances to, I would always chose to stay faithful to our allies.
And by the way, saying that the US protected Germany for 70 years is just false, until 1990 there was no peace treaty after WW2 and those were essentially occupation forces willing to sacrifice Germany as a battle ground to be destroyed in WW3. This isn't exactly protection, and after the threat of the SU vanished the US weren't needed as protectors, they just stayed, used Germany as a logistics base and that's it.