While mp3tag has been already amazingly well designed, the opening next folder button might be a good idea.
That's when going through a longer folder with album folders, one has to use Change folder button and scroll down to the next folder one by one ...
So far the idea is always: use Windows Explorer if you are missing any file handling functions in MP3tag.
So have a Windows Explorer window open in which you navigate to the desired location and then either drag&drop the files and/or folders or copy&paste the path from the Windows Explorer to the directory field in MP3tag.
I also can find my way to the desired folder but I still think it would be a good addition to have these options. I have no idea how hard it is to add it?
Please see the linked thread plus the threads that are linked from there.
They might give you an idea what to do in the meantime until the feature is implemented and how many alternative workflows may be used that may be even more powerful than just a look at single folders.
A footnote: the also discussed feature to select all files when MP3tag starts has been implemented in the meantime.
I disagree. There is a quick and easy solution available right now. In Windows Explorer right click on the desired folder and choose Mp3tag from the context menu. Not only will that load that folder but it will automatically replace the current contents in Mp3tag. Done!
That works indeed! Mp3tag is only not direct visible in the context menu (Win11), I need to select More choices to see the additional ones including mp3tag. But this is far better than copy/paste.
Or you can press SHIFT + Right Mouseclick on Windows 11 to directly get the "expanded contextmenu" (the same as manually pressing on "Show more options"/"Weitere Optionen anzeigen"), including Mp3tag.
There's a third party software called Windhawk that allows users to modularly modify many aspects of Windows 11. One of the mods is to “always show more options.” I find it useful.