Somebody has suggested to me to use the zoom "Call me" feature (which isn't available unless you're calling into a meeting with somebody with a paid account who has "Call me" enabled).
I've always used only "Join from Your Browser", i.e. the web app version of zoom, not the app. However, though the call me support page does not list the app as a requirement (and neither does this page about enabling "call me"), the similar feature "Dial in" doesn't seem to be present in the web app version. Does "Call me" work with the web app?