is there a function to unfix the Start/Browse/Radio part in the Desktop app? So that it scrolls with the playlists and doesn't stay fixed as top 3 in the left bar?
Windows 10 - Spotify App
That function has not been implemented in the current version of the desktop app. What you could do, if you'd really like that function for future versions, you could submit that idea via this page.
Hope this helps!