Hi Tobias, thank you for your kind words :)
I’m happy my series has been helpful. Unfortunately when it comes to German retirement plans I wasn’t able to find simple and helpful information (mostly because, well… I can’t read German).
I’d recommend you look for popular finance bloggers in Germany. The reason I say bloggers is because (like you said) they don’t have any incentive to sell you anything that isn’t in your absolute best interest (or at least they shouldn’t… If they’re ethical). I tried finding something good (maybe this helps).
I hope this helped in any small way! Sorry I couldn’t do more.