I will likely edit and expand on this within this same post to keep all info together.
Early august 2023, Vagabond creates a thread on the Topic "New World Map". Since in general I like maps and also like 3D design making a 3D viewable World Map seems an interesting creative challenge.
I already browsed through some examples of three.js some time ago, a looking for more specific examples I came across the following link:
https://nathanpointer.com/blog/landscapes/
which comes with this example and a short explanation of used technology.
He references World Creator, but this is not a free tool, so for now I will see how far I can go with Blender and if Blender can use splat textures. I will try and update every 2 weeks.
After some exploring turns out Gaea has a free landscape editing version. Going through the tutorials.
Cya in game.