LO transparent text

Layout text can be filled with colour, that colour can be set to transparent… but the transparency is not displayed. Is this a bug?

P.S.:
someone back in 2016 asked exactly that: the ability to make a watermark in LO.
https://forums.sketchup.com/t/how-to-make-a-transparent-text-in-layout/23773
P.S.S.:
I am aware of SU workarounds and adding a watermark on pdf`s in Adobe Acrobat.