Landscape Material: How many textures is optimal to put as maximum with World Composition?

Hello, I am creating my landscape material from an open world map (created with World Composition) with several biodomains, such as the desert, the forest, the coast, the mountain, etc.
So I have more than 50 textures needed for my world.
Is it better to create a material with all 50 textures or is it better to create several materials for each landscape of my world with which they are used only at that level (maybe 10 to 20 per landscape)?

While there is no limit like that imposed, having more than 16 landscape layers in material greatly reduces comfort of working with it and inflates iteration times. So splitting it up would not hurt. Additionally you can’t expect to have more than 3-4 layers painted per each landscape component. In given context, 1 landscape layer is though to have 3 textures.

Thanks for the answer!