If you can selfhost, you can try my SyncMarks AddOn. It will work on any webextension compatible browser, e.g Firefox, Chrome, Chromium, Edge, Brave, Kiwi and so on. You can sync across all Browsers.
The backend is working with selfhosted PHP/MySQL (or SQLITE) stack. If you can’t use this, you can fallback to WebDAV as backend, but with limited functionality.
The addon can work together with the standard sync mechanisms in all these browsers, but it’s up to you if you want that.
If the addon is not installed, you can access the backend url with any browser and use it as WebApp. With apps like Tasker or HTTPShortcuts, you can share any url, from any to the backend.
Darktable? It’s a RAW developer and photo managing software on Linux, Windows and Mac, a little bit like Adobe Lightroom, but OpenSource. If GPS coordinates are in the RAW, sidecar or jpg files, the photos can be displayed in the map module. Much better, if you have a GPX file and no GPS data embedded, you can assign the photos to the GPX route, as long the timestamp of DateTimeOriginal in Exif is accurate. If the timestamp differs, you can specify the difference.
Maybe Digikam can do the same. But I don’t like the KDE framework which is used there. Digikam is available for Linux and Windows (yes, I know it’s strange).