Note that this was in no way meant as a criticism of your excellent work. I checked the admin level sheet myself for The Netherlands, I didn’t realize what the effects would be for smaller towns, until I saw it in action.
Out of curiosity: when there is a new data update from OSM, will the current cities stay the same, or will you import the cities again according to the admin level at that time?
Example: the town of Weesp is set to join the municipality of Amsterdam (probably in 2022). If that make it to OSM, will that eventually mean Weesp is no longer in Citystrides?