The folium package is great, but I recognized a problem with the heat maps: They only show the density of places, not the density of the events. I tried to change the weight for the places depending on the number of events, but it seems to have no to very little effect.
I afraid I probably need chloropleth maps with devision on municipal or parish level to create what I was looking for, but it is much more difficult to get geodata for them as well as exporting the event places from my place hierarchy instead of using the coordinates.
My current workaround is using circle markers colored depending on the number of events.
