Tried making a jungle mountain with gaea 2
In This i used a low poly mesh of the terrain used 8k base color and normal maps and a 16k displacement map for pushing out the fine details
This way i managed to get 16k results without using any super high poly plane
if you want to have this terrain you can get it for free here:
https://www.cgtrader.com/free-3d-models/exterior/landscape/16k-jungle-mountain