It has been requested a few times already, so I'm sharing here the patch I made for Folkvangr and Realistic Grass Fields. I've also added the modified ESP for Folkvangr, which removes all the worldspace edits (way better for compatibility).
If you want to get the same results than me, then you also have to set iMinGrassSize to 40 and iMaxGrassTypesPerTexure to 15. For these changes to take effect, you'll have to delete Folkvangr's ini file (or make the changes directly in it).
Finally, if you are using a recently updated ENB, I heavily recommend you install the Folkvangr and Realistic Grass Field patches for complexgrass effects from this page : https://www.nexusmods.com/skyrimspecialedition/mods/67304?tab=files
Cheers !