In "LibreOffice Draw" settings dialog box there are configured properties like "scale" and "units" which are specific to document mixed with global settings like for example grid settings.
I propose to separate "per document" settings from "global" settings in some way.
For example move them closer to the page format settings.
Good idea but actually a duplicate of tdf#59068 in respect to the scale values and (your) tdf#78035 for the grid lines. Closing this one.
*** This bug has been marked as a duplicate of bug 78035 ***
This one is about the UI presentation in Tools > Options ...