Are variable-width fonts easier to read than monospace fonts?

Good grief. We need to some sort of people’s cooperative just to fund basic usability research it seems. How can such a straightforward and relatively important question, that’s also very easy to test, not have any well-known research citations?

https://ux.stackexchange.com/questions/48753/does-the-use-of-monospaced-fonts-negatively-affect-legibility-of-article-text

I finally searched in Google Scholar (not linked from the main google page as a search option anymore, yikes) in order to get actual scientific studies to cite:

More recent research testing children’s reading efficiency also supports variable-width fonts over monospaced: https://www.tandfonline.com/doi/abs/10.1080/01449290210146737

In response to the mention of dyslexia with regard to monospace fonts being better, and a commenter being interested in research on that:

Even more recent research on dyslexia cites “character width” but it’s not clear from the abstract if monospace fonts were tested, nor which was better. https://link.springer.com/article/10.1007/s10209-015-0438-8

Aside: I have mild dyslexia and doubt that monospace, other things like size being equal to the greatest degree possible, is an advantage.

Moreover the ‘river effect’ of white space is apt to be worse with monospace fonts. It doesn’t affect me much but it’s reported to be associated with dyslexia.