I dont think you are using a good export file.
If you were, the results would be identical to what you see in whatever editor you are using - in this case Gaea.
Unreal works with individual tiles for larger worlds, so a map of 10,000 units or just about can probably be split up into 4 smaller tiles of around 4k each.
Again - the files that any program allowing you to edit the terrain exports are not images. Can’t stress this enough.
You cannot just edit them to cut them up in anything. You have to use a specific program that supports 16bit format.
Landscape detaile is essentially locked to one vertex per meter.
Changing scale of x/y changes this so you can do things like 1 vertex every 50cm instead (at 50% scale). This generally leads to performance degradation.
Again. The heightmap not being an image, means that resolution of it is unimportant. A pixel is the data of the height. The amount of pixels doesn’t really change the quality or distribution of said data.
Probably overstressing the GPU with the scale value you selected. Hard to know. 8k tiles aren’t suggested for regular systems.
A 3060 isn’t horrible with likely 4gb.
However your heightmap alone is around 1GB or close to it probably, and the engine doesn’t really do well with files over 8k in size even when you custom modify source to handle them for VT.
No. But start from scratch by exporting the proper size file and importing it into the engin in the proper way.
If you want performance the first thing you ought to do is create 4 landscapes tiles (all at the same size) and benchmark your scene cost when placing the camera/player at the nexus of the 4 tiles.
Play with changing different tile sizes and find the configuration that best works with your system - move on from there by importing the actual heightmap and materials into it.
Once you reach that spot, if you are still getting jagged edges and issues with the file you exported, then you should get back to the forums to debug further.
Chanches are that withe a proper export you won’t have any issue though.