Redhat 8 doesn't ship with menu editing support. The code was broken when they shipped, and it was fixed 2 weeks later iirc. Life sucks sometimes
The Linux menu system is somewhat in flux currently anyway, it'll all be sorted out in 8.1
For now, if you absolutely MUST edit the menus, you can do so by altering some text files.
For NTFS see linux-ntfs.sf.net - they have instructions specifically for Redhat 8. Most other distros ship with it included, dunno why the 'hat don't.