Germany’s “Much needed baby boom” is what should be coming from their native Aryan population creating and raising them, much like in America and England. Any attempts to find a replacement for the young people who never saw the dawn due to infanticide or their parents going queer are going to fail miserably even if their host nations gave half a damn about assimilation, which they don’t.
If memory serves ~80 years ago a funny little man steamrolled an entire continent with little more than enshrining this fact in law, some half-baked nationalist propaganda and a government half-staffed by circus freak show rejects. I think we can safely rule out the latter two as factors in his success.
The native ‘aryan’ population is weak and neutered. Toughness is no longer in their DNA. They can’t build a strong military force with effete snowflakes in skinny jeans.
So they have to import this toughness from some place else.