Demo with a single group: example1. This shows the mean daily max temperature averaged over one year, averaged over the period 1990-2020 for Météo-France stations in Brittany, France (source: Météo-France)
Demo with two groups: example2. Similar data but we have arbitrarily separated it in two groups, main and secondary.
Demo with a single group but with a lot of markers and collisions (to assess performance for your use case) : example3. This looks a lot like the first example but with temperature for a specific day in January 2024 from many stations by Météo-France and other providers (source: MétéoData). Notice how we leverage the zoom event to hide the deflated icons on lower zooms tofurther improve legibility.