I agree to some extend, but I don't think this explains the low birth rate compared to other very similar countries like France, the UK or the US, where many of

I agree to some extend, but I don't think this explains the low birth rate compared to other very similar countries like France, the UK or the US, where many of the things you describe apply equally or in greater measure. An aspect that seems more uniquely German is looking down on mothers that give their child to daycare "too early", meaning, before it's 3 years old. Anecdotally from conversations with friends in their mid late twenties, early thirties, the idea that you have to justify yourself as a woman, or somehow fail as a mother, if you start working again too soon is still very prominent.