So many questions, but all the result of research so it’s fair game. I’ll answer a few.
1. The Dutch weren’t silly enough to try to make their own bottom bracket standard, or at least weren’t successful enough for it to become common. More on that here:
https://www.sheldonbrown.com/cribshe...mbrackets.html
2. If you want to read more about some of the far too far many threadless BB standards you can do so here:
https://www.sheldonbrown.com/cribshe...mbrackets.html
3. There are two almost but not quite the same square taper standards. More on that here:
https://www.sheldonbrown.com/bbtaper.html
Other notes: Gazelle has been around a while. They got their start importing UK made bikes if their Wikipedia page is to be trusted.
https://en.m.wikipedia.org/wiki/Gaze...cycle_company)
If someone makes a direct replacement marketed for your bike and it’s reasonably priced I would start there as a default.