You are running fedora which is using the dnf package manager. The commands you mentioned (apt/ppa) are part of the apt (aptitude) package manager which is comes with Ubuntu.
Apt is the command to install/manage packages on Ubuntu (and other distros that use apt). A ppa is a special way to tell apt where it can download packages from. It lets you a install 3rd party packages not provided by your distros default selection. It is specific to apt and will not work for dnf.
This isn’t the end of the world and you can still install the package. Because these packages are open source, you can build the package from source. The instructions for which can be found on the github readme. Hopefully this cleared some things up!
[Edit] done some poking around, and I managed to get it running on fedora. I had weird issues building it from scratch, so I did it in a janky way by downloading and extracting the deb (it had precompiled bin inside). Looks to be working tho I couldn’t test it because no qemu