Question How should I sculpt little details in terrain?

So earlier i did some maps for squod shooter and disided to try making some game, for my project i chose low poly walikng /trail game , for the satrt it seems to need minimal skripting and i will learn to make simple low poly stuff in blender now i am trying to figure out best way sto start building my world, so in recent days i managed to import some mountainiuos terrain from world.party to unity learned some stuff in the blender, but i cant find the proper way to make detailed trail terrain, at first i was thinking i will downsize some brushes and just brush everything, but either my terrain settings are incorrect or i am doing something very wrong because brushes either do to much damage or if i make them very small they stop working, so searched i searched how should i adjust my terrain.
Played a bit with texture resolution settings:
Heightmap resolution 4097x4097
control texture resolution 512x512
base texture resolution 1024x1024

but i wasn't able to make small changes to my mountain terrain and best i got smooth river bed like snake , so i tried making some assets in blender with fine detailing and when laying this thing on top of unity terrain. seems like it could be done, but it looks like to clunky way to do it and i don't know how it will effect performance... at the moment best i could think if its possible is moving whole mountain terrain to blender subdivide it to infinity fry my computer, sculpt it in blender and move back to unity...

my ideal scenario would be if i could just use brushes in unity to make these detailed trails i want, maybe someone knows what would be a proper way to do trails with lots of uneven ground
i atached some images of my stuff

 

For small details don't modify the heightmap directly, just use high quality textures and a terrain shader that supports parallax mapping or tessellation.

Then you can just paint the terrain with an appropriate material (eg pebbles and dirt) and the extra geometric detail will come from the lighting and displacement texture of your materials, and not the terrain heightmap.

For slightly larger details like rocks and bigger pebbles, you can just use the detail painting system with appropriate low poly meshes.

 

that would be good but if i understand it correctly this way will give me just visual look and ect but ground will stay flat because of my english i find it hard to explain what i have in my mind, my biggest problem comes from my wish to have these bumps and potholes for rag doll walking mechanic to be able step on it or trip and ect and when on top off that drop some rocks branches and ect ... not just visually look like where is some bump and ect. , I realized if i make very small terrain tile when it has enough detailing for brushes to work how i want and i am actually able to sculpt it to my liking with default terrain settings, i made quick patch of ground and added few pics for better understanding ... i see i can create much terrain patches with individual settings, so probably if i figure out how to do tiled terrains in unity, i will be able cut my whole terrain in the smaller patches and only use patches which i need for my hiking road and rest of them i can set way below default settings and safe some performance? green hills is big terrain and i cant sclupt it as i want , small patch with sand texture and rocks is good enough for me to work with