I think the grid might be coming, if not it would be a good feature request.
Categorization improvements same.
Music player for backing tracks I believe is there today either in current stable and maybe improved in test, you should be able to find and I’ll put a pointer to User Guide later if needed.
Are you aware of the “Vangelis” AKA Testing version? It may have what you want, but of course you have to decide if you want to handle the headaches of a test version, or just wait, and perhaps make suggestions.
I can’t find the recent discussion of improvements to audio player but I know I saw it go by re a backing track.