There seem to be at least two topics mixed together here.
From what I could observe so far, grass in MSFS2024 seems to be drawn in clusters (or blocks or whatever you want to call them), so if I’m not mistaken, sharp corners are not possible anymore. I’d be gladly corrected if wrong about this. Also see this post where observations about this (MSFS2020 vs. MSFS2024) have been shared:
It is not clear yet how particular grass types can be called other than via biomes (which - on the other hand - are not fully supported yet). See my most I made about that yesterday: