Running the same memory constraints on a 1.18 vanilla instance, most of the stack memory allocation largrly comes from ramping the render distance from 12 chunks to 32 chunks. The game only uses ~0.7 GiB memory non-heap at a sane render distance in vanilla whereas ~2.0 GiB at 32 chunks. I did forget the the render distance no longer caps out in vanilla at 16 chunks. Far render distances like 32 chunks will naturally balloon the stack memory size.