On the now defunct Banshee mailing list (firstname.lastname@example.org). Nicolas Krzywinski asked on 11 October 2020 if it would be possible to provide the Banshee 20.04 binaries.
If I remember correctly, I had to manually find and install missing dependencies to get Banshee working on Ubuntu 20.04: libgconf2.0-cil, libgconf2.0-cil-dev and libmono-corlib4.0-cil. I think I got the Banshee DEB package from the 19.10 repository. I just tested Banshee after upgrading from Ubuntu 20.04 to 20.10 and it still works.
I would be pleased to help by providing my installed binaries, or export all the necessary DEB packages. Do you still need them?