It should be possible to install via the official script with --no-dkms as mentioned in the previous posts.
@sugarbravo confirmed successfull installs on 19.10 and 20.04 (alpha). Read above.
In the original post i basically followed the instructions here with adjusted deb names of the recent amd package.
Even though nothing gets installed via package manager this way, there are some manual commands with elevated rights. This might not be for everybody. Be careful. Therefore I prefer the use of the amd install script with --no-dkms.
Both ways work on my system