sometimes it recovers when I wait 5 - 10 minutes but usually I am not patient enough to wait, so I force restart using Process Explorer, as closing Firefox directly through its UI is blocked out.
Firefox 125.0.2 loves hanging (about every 3rd time) in Windows 10 Pro, when I save any document / image. Can't even start to write the file name and obviously not close the "save as..." window. Usually force crashing and restarting the browser solve...