perhaps it is already the case, and if it is then wow
Unfortunately no, this plugin is still not there yet!
This is the best you can do right now:
One limitation is that the RGE API only allow for 10k pixels heightmaps.
So you can make manually 7x7 = 49 different landscapes to get 70k pixels.
You would import one landscape, then save, unload, and then do the next one. Very tedious!
Also the problem with this is that you would have many landscapes instead of one, which might be annoying to deal with. They should align properly, but it’s possible that the border will be visible, and it will be annoying for roads or other assets which are crossing landscapes.
Another possibility is to manually download the RGE tiles for your area, and I believe they are 1k tiles. So if the area is a 70km square, then you would have 4900 tiles. You can try importing all the tiles as is, with the default import method of Unreal Engine, but I don’t know if Unreal deals with that many files properly. I had the impression that everything was loaded into memory at once, so it wouldn’t work. Perhaps this is something Unreal will improve in the future, or maybe it already works?
I opened an issue here to keep track of this feature in my plugin: