Hi MiKa(@photoweblog), installing Geonode is a little bit tricky, but possible.
and indeed it is a good tool with different potentials, unfortunately I have not found a great presence from the developers, but it could be that they are much more willing to a developer able to open their creature to WordPress.
In fact, the developers of Geonode have stated the compatibility towards WordPress and Drupal, but in fact they have never done anything in this direction!
If you go to the the interoperability web page, you will notice the WordPress and Drupal compatibility, what totally disregarded.
Coming back to your question, I’ve try to install on Ubuntu 20.04 server, using native deb method and Docker method.
I suggest you the Docker one, most simple and with more consistent documentation information compared to the previous:
DEB native: https://docs.geonode.org/en/master/install/advanced/project/index.html#ubuntu-18-04
Docker: https://docs.geonode.org/en/master/install/basic/index.html#ubuntu-18-0-basic-setup
Let we know ??