I’d like to change my distribution but when I attempt to create a backup through steam, it just creates an empty folder with the game’s name.
I’m assuming this is because how flatpak contains the app.
How can I make a backup of my games so I don’t have to redownload everything again?
Unless you've added custom library folders, this is where the files live:
$HOME/.var/app/com.valvesoftware.Steam/
Go to ./var in home and backup the entire "com.valvesoftware.Steam" folder if you plan to use Flatpak again, or navigate to data/Steam/steamapps and copy just the stuff there. For native games you might have to look inside .config and .local in "com.valvesoftware.Steam", that's where games usually store their config files and saves.
Thanks, that really helps. Copying everything sounds like the quickest and simplest way but it's good to know that everything is easily accessible.