The present configuration of Bookmarks:
Both “areas” of Bookmarks are linked, deleting from one will update the other. Neither are isolated personal storage areas for selected bookmarks of the user’s choosing. You can’t keep/delete one bookmark in one area (Bookmarks toolbar and/or hamburger icon > Bookmarks) without the action being correspondingly reflected in the other area.
The hamburger Bookmarks is very convenient for me, but I only want links in it that are temporary.
In the event I wish to keep them on a permanent basis, then I would then add them to my Toolbar Bookmarks.
As you may know this presently cannot be done, whatever happens in one version of Bookmarks correspondingly happens in the other.
I am not happy with this arrangement, and would like to bring this anomaly to the attention of the browser developers please.