While profiling the openXR branch where even the default cube only runs at a disappointing 45 fps i stumbled upon drw_engine_init running every frame and doing some rather expensive operations every single frame which is 'not great'
we recently removed one of those operations from the GP init but there's still plenty of others left
A quick profile shows the following flame graph
Both GPU_Draw_List_Init and GPU_Buf_Alloc seem to trigger behavior in the nvidia driver that causes it to spin off a thread and wait for it to exit, not something you'd want to do every frame (or multiple times a frame, hard to tell from a flame graph)
Discussed on chat and you requested a task low prio task for this for further investigation