I’m aware LibreOffice has a toggle that will allow supporting fonts to be given an outline, specifically being the “text color” where the internal is left white. Putting aside the desired functionality of changing the outline and fill color separately, I wanted to know; is there a way to increase the size of the text outline so as to make it thicker?
I am not aware of any way inside Writer.
I’d create some text in Draw, select it and Shape>Convert>To Curve. Then I can process separately the “inside” with Format>Area and the “contour” (or 'outline") with Format>Line.
What you process so become a drwing or an image. Therefore, you may meet problems when inserting it back in Writer (and somewhat fewer in Impress). These problems are related to interaction with “main text”. Also, Writer will consider it as a Drawing Object, which means you can’t control formatting through a frame style. Formatting is manual only.