You don’t have to use Landscape Material Layers. You can simply use anything in the material editor instead. You can combine it with landscape painted masks, but you don’t have to 
But I agree in general that Landscape leaves a lot to be desired. Especially now in UE5, with tessellation being deprecated, virtual heighfield workflow being still clumsy and unfinished, the landscape resolution is just not on par with the rest of the next gen UE5 feature set and leaves much to be desired.
Almost entire UE5 is migrating to the next gen, high fidelity graphics, but with landscape, we still have the good old 1 meter / landscape texel resolution, which just doesn’t cut it these days even with help of normal maps:
and especially with either ray traced or virtual shadowmap shadows, which make it way more difficult to hide the low res topology of landscape up close.
There are some clumsy workaround such as scaling down the landscape, but then it requires many more landscape components to cover large areas, and the performance goes down the drain even on high end hardware.
It’d be nice to get some new nanite-style landscape tessellation which could get us at least 10CM resolution, instead of 1M, while maintaining at least comparable performance.