Generally the automated layer adds too much overhead to the shader complexity.
I have my material running in this way.
Auto layer - if you fill this layer you get the automated base.
Separate layers - coloring these over the auto layer destroys performance.
Once you are done painting over the auto layer, delete the auto layer.
result is usually a somewhat fast landscape material. Depending on shader complexity and tile size that was chosen anyway.
While I no longer use the layer blends that come with landscape as their performance is incredibly bad, you can probably just copy and paste (provided you aren’t using 4.24 or that 4.24 shader paste bug was fixed otherwise you’ll have to deal with a lot of re-wiring) your auto material into a material function, out put it to different pins, and do the same thing one normally does for a single layer.
You can then call the material function within the landscape shader and assign it to the auto layer you simply add to the list.
You may want to change the order of them. Again, haven’t played with those landscape layer nodes since 4.21 when I realized just how bad their performance was over simple add/subtracts.
I would suggest having the Auto Layer as the starting point / first entry, the other layers following it. However this may not matter one bit…