[1]:https://www.populationpyramid.net/germany/2023/
What you describe is true in the US though. They have been able to 'cheat' by getting the cream of the crop via immigration to bolster their numbers(although its now fraying post Trump). Without that immigration, they would probably be mirroring German numbers.
[2]:https://www.populationpyramid.net/united-states-of-america/2...
What's up with your racism and hate? Literally No one is colonizing you
1- Foreigners account to only 17% of the population (and 70% of them are from Europe) [1]
2- If we look at countries with the highest proportion of immigrants, Germany is no. 18 on the list [2]
If you've an issue with people from outside Germany moving there, change your policy. If there are problems, fix your system. That's how every country work.
jeez, do you still live in the middle ages?
[1] - https://www.destatis.de/EN/Themes/Society-Environment/Popula...
[2] - https://www.visualcapitalist.com/countries-with-the-highest-...