In QGIS you could render something like the graphic you show using the geometry generator marker option.
Each cardinal direction could have a field associated with it - N, NE, E, etc.
Each triangle would be built using the coordinates ($x, $y) of the point and rotated depending on the compass direction:
Macromedia Freehand - if the year was 1999. Thats what i used when i was at University, to do a very similar project.
Jokes aside though, the point im making is that perhaps this is less of a 'GIS Software' question and maybe more of a 'multimedia software' question?
You could potentially create the windmills in said multimedia software and then ave them as ....
Cutting up your MultiPolygons might help with rendering at higher zoom levels. I must say its odd you get worse speed the more you zoom in, that sounds like postgis is struggling to cut of the large polygons and serve to geoserver.
Something like this would work to quickly separate the large MultiPolygons. Using ST_COLLECTIONEXTRACT will return only a ...
It doesn't contain every item in my wish-list but is a great place to start.
With qgis2web export leaflet you can create a nice map.
But I think, a directly link is not possible.
However you need for all regions informations, for example the name of a region. And in addition you can insert hyperlinks to other internet pages. This ist not a problem, because you can insert html within the table.
If you insert https://www....