As far as I can tell, without tesselation the most resolution you can get from the landscape is 1m faces. I think that if you are wanting what appears to be less than 1m resolution, you’ll want to use a height blend layer type in the landscape material.
This will break the blending up from being linear and make it look more natural, based on your textures height texture.
It’s a bit to setup but there is many tutorials on the subject:
Landscape Textures - Building Worlds In Unreal - Episode 3 - YouTube
Intro to Unreal Landscapes - Alpha, Weight and Height Blend Modes - YouTube
I always caution though - don’t evaluate a single aspect of the total art in isolation. Assuming you will have grass, trees, and other props breaking up the landscape, you may be solving a problem that won’t actually exist.