ForgedAnvil
Explorer
Using LibreOffice there is an issue that the option can not be disabled, you can enable an option but not disable any, including an option that you enable.
Also how do I choose the subrace?
I have never used LibreOffice before but suspect that it doesn't support (or partially supports) conditional formatting and data validation.
To "disable" an option just clear the cell (in Excel there is a blank value in the drop down list)
Subrace only shows for Races that have a subrace (e.g. Elf) and should appear when the user selects a Race that has a subrace. It will show in the cell below Race.