Gmail never displays in its latest version on Firefox, only in HTML -- for several years now.

I have been unable to use Firefox for Gmail for several years now. I use Chrome instead, because whenever I try it on Firefox, I get the following message: Do you really want to use HTML Gmail? You're about to use a version of Gmail designed for slower connections and legacy browsers. To get all of Gmail's features, including inbox categories, images and quick actions, please use the latest version of Gmail (recommended). When I click on the box marked Take me to the latest version, absolutely nothing happens. If I click on the box for the HTML version, Gmail appears, but devoid of anything resembling Gmail as we know it now. Much as I want to use Firefox for everything, I can't, because this is a serious limitation. Am I alone with this problem? It has happened on two different laptops (Macbooks).