Yes, why would it?
Nothing you do within a material shader has any impact with how many objects are on screen in this case
Ofc if you set the opacity to 0 on the object they potentially get culled/not rendered.
To somrhow change the drawcalls you’d have to aggregate landscape pieces together - say with HLODs for instance.
Its not how many materials total that give you the number of drawcalls.
Is how many materials on a single mesh -1 for the mesh itself.
So if you have 3 materials on 1 object, and spawn 10 copies of that object, that’s 30 draw calls.
It really depends on how you map and set up the material. Even something ridiculously small can look good when set up properly.
Start at 2k. Move up if you cant get it to look right.
You can do some basic math of how big a pixel is in world space by just assuming that the height/width of the texture marches the size in km of the landscape’s total.
So if you have a 2k map distributed on an 8km tile, you then have each pixel cover approximately 4m^2 I believe.
Depending on what kind of work you do in the material that can either be a lot of resoluton or very little… it really just depends on art direction a lot too.