Fedora Linux devs discuss dropping 32-bit packages - potentially bad news for Steam gamers
(www.gamingonlinux.com)
Isn’t Bazzite built on Fedora Silverblue
Kinda.
installs the Steam Flatpak?
Actually no. Bazzite installs Steam from the RPM Fusion repo.
As for an attempt to shed light on why Fedora is absent from Steam's numbers, see this comment. Finally, perhaps this is worth looking into to see how big Fedora's gaming community is compared to the rest of its users.