I found an article indicating that starting in Firefox 102, Linux users have GeoClue enabled for geolocation. If you wanted to roll that back to see whether it is a factor, or turn it back on if needed, here's where you'll find that:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste geo.provider.use_geoclue and pause while the list is filtered

(3) To toggle between true (enabled) and false (disabled), either double-click the preference or click the toggle button at the right end of the row. I don't know whether this takes effect immediately or after your next restart.

(I don't have this on Windows, so don't have the ability to test.)

Note that the Firefox version from the Linux repositories may not come with all special keys.

keyLocationServiceGoogleFound: FALSE
keySafebrowsingGoogleFound: TRUE
keyMozillaFound: TRUE

I suspected that the system was relying on reported wifi SSID location matching - which will be WRONG if a number of routers (more than one) have been moved wholesale as a group - to a new location - which is of course precisely what I have done.

Turning geoclue off results in a less precise location - but in the right general area... which is good enough to be considered as a fix! The moral of the story is that these clever systems do often come with a peculiar set of circumstances under which they will fail... sometimes because nobody thought they would ever be encountered.

So in this case, GeoClueless. I wonder how that is supposed to eventually get updated?