> Whereas grandma on Windows and Chrome is "less unique," and therefore in some sense less fingerprint-able.

I think the problem I have with these types of sites is that they do not really offer advice on how to become less unique and how to protect one's self. It's probably pretty easy to identify machines through things like canvas fingerprinting or through all the other things that the browser actually exposes. Many privacy browsers like Tor or Mullvad will just send no data to those. That makes them "unique" because there's not many people using browsers that do that but it's unique in a way that makes you fungible. There's unique as in "uncommon" but also unique as "differentiable." I can't understand how these sites never make that distinction.