After researching and not coming to a solution or idea, I am going to ask the community here.
Is it possible to upgrade packages in Ubuntu 18.04 LTS to connect with NetworkManager from the GUI to WPA3 protected networks, and if so, what packages or what config is to set up?
I'm curious for your answers.
As @adasiko said, You need NetworkManager 1.16+ https://blogs.gnome.org/lkundrak/2019/03/15/networkmanager-1-16/
This version is available first in Ubuntu 19.04 Disco: https://packages.ubuntu.com/disco/net/network-manager
The easiest way to get it is probably to upgrade to that release. However, I don't see WPA 3 in the drop-down in the GUI in that release, so this still isn't a great answer.