You phrase this as if it’s absurd. Why should it be possible to offshore your future capital gains without paying an exit tax? You live in a country with a tax system that assumes people pay into it.
Unrealized capital gains taxes generally are a bit absurd, but I can see how the state would feel forced to do it if you're leaving. Seems like there should be some way to get a registered agent or something to keep the old company legally "in Germany" while you leave, but idk