Done some testing and tried stuff like world partitioning without success, so far a decent workaround for me was just thinning out excessive amounts of grass which works. You can also thin out further and increase the XY(Z) scale values of your grass since the problem seems to be related to the amount of grass meshes. On that note I think just making groups of grass clumps in your 3d program of choice that contain multiple grass blades positioned together and combined in a big mesh would also work, haven’t tested it though.