Unity 3D on Fedora 31 Linux distro.

First, you need to have good hardware to run the Unity 3D software on Fedora 31 Linux.
To install on Fedora 31 Linux is easy to do. You need to download the Unity beta application from this website.

[mythcat@desk ~]$ cd Downloads/
[mythcat@desk Downloads]$ chmod +x UnitySetup-2018.2.7f1 

You need to install this package for this file: libgconf-2.so.4

[root@desk Downloads]# dnf install GConf2-devel.x86_64

The next step is simple run the installer and follow the interface...

[mythcat@desk Downloads]$ ./UnitySetup-2018.2.7f1 

If you want to use a free license then you need to save the license from application into the file named Unity_v2018.2.7f1.alf .
Using the Unity website manual activate the free license and download the file named Unity_v2018.x.ulf. You can use the UnityHub.AppImage from Unity official website to install any Unity 3D version:

[mythcat@desk Downloads]$ chmod +x UnityHub.AppImage 
[mythcat@desk Downloads]$ ./UnityHub.AppImage 

See the screenshots: