Later versions of unity need GTK+ 3.4 http://www.linuxfromscratch.org/~thomasp/blfs-book-xsl/x/gtk3.html
https://forum.unity.com/threads/unity-rpm-package.460068/
https://gist.github.com/blaztinn/f92739cd23aceb6dcb9c1b0e47739cfc
http://allnightburger.com/installing-unity3d-on-fedora-24/
https://gist.github.com/bobmoff/8d5e1fc1e47b71bf33e53a2e55a62aff
Automatic updates are now supported in GNOME 3.30 via Flatpak in Fedora 29. Flatpak is a package management utility for distributing desktop applications on Linux.
xdg-app now FlatPak / flatpak $XDG_DATA_HOME/unity3d/Unity (local storage for the license information is stored in) so this means unity editor is delivered via flatpak it would seem https://wiki.archlinux.org/index.php/XDG_Base_Directory Many game engines (Unity 3D, Unreal) follow the specification, but then individual game publishers hardcode the paths in Steam Auto-Cloud causing game-saves to sync to the wrong directory.
option 1: vnc https://github.com/sjb8100/docker-unity3d https://forum.unity.com/threads/5-4-0p1-fails-to-launch-due-to-license.425277/#post-2941499
option 2: https://github.com/GabLeRoux/unity3d-ci-example/blob/master/README.md
could work, first look at game for steam https://github.com/flathub/com.valvesoftware.Steam