This script allows you to apply double spacing between words in LibreOffice. How to run? Tools → Macros → Organize Macros → LibreOffice Basic → New → DoubleSpaceWords. Then follow the same steps again, but this time click on Run and select the module you just created.

DoubleSpacesBetweenWords.vba

Sub DoubleSpacesBetweenWords
    Dim oDoc As Object
    Dim oReplace As Object
    
    oDoc = ThisComponent
    
    ' Create a search descriptor
    oReplace = oDoc.createSearchDescriptor()
    
    ' Search for a single space
    oReplace.SearchString = " "
    
    ' Replace with double space
    oReplace.ReplaceString = "  "
    
    ' Do global replace
    oReplace.SearchAll = True
    
    ' Execute replacement
    oDoc.replaceAll(oReplace)
    
    MsgBox "All spaces doubled!"
End Sub