You can use position in Web Mercator, but to give it to an object on the map it will need to be converted to coordinates or position objects on the map yourself.
Conversions between coordinates and Web Mercator projection are pretty fast and without GC allocation.
You can also convert coordinates to Unity World Position.
If you want, you can write your own methods to convert Web Mercator from/to Unity World Position.
Without geo coordinates it will work VERY fast.

To summarize: you can work with your objects without using coordinates, but you will need to make your own system for managing and positioning objects on the map.
This is absolutely not difficult.

I'm currently thinking about switching from ArcGis Unity to this asset. I am building an application in which I have to move many, hundreds of objects on the 3D map based on web-mercator positions from the backend. Like some sort of simulation, but without being able to predict the position. Therefore, the asset I choose should be performant, especially the movement of entities on the map.

Hence my questions:
- How performant is this asset in such a case?
- Does garbage occur when you move a marker?
- Are there other ways besides markers to set objects so that they appear correctly on the map according to their geo-coordinate (can I convert lat/lon or web mercator to unity coordinates so that they correspond to the position on the map)?
- Can I use Web-Mercator projections/coordinates instead of Lat/Lon?

Thanks!