So most printers in the past decade support driverless printing. It seems that yours was made right before the transition from drivers to driverless support.
If you’re trying to use RPMs, then you’d need to do
rpm-ostree install *rpm (assuming those are the only RPM files in the directory). Silverblue doesn’t support
dnf, except in toolboxes (which are not the host system). But you need printer drivers on the system, not in a toolbox.
However, years ago, this method did not work with various printer drivers, as they sometimes try to put files in /opt/ which doesn’t work as expected in Fedora, especially Silverblue (which, at least at the time, did not support that). But since then, there has been work to support a subset of RPMs that place things like drivers in /opt/. I believe this was with relocatable RPMs? Anyway, it might work now, and you should definitely try it.
So, in summary:
rpm-ostree install *rpm (or the RPM file names), then hope it works, and reboot. Then it might work? But it also might not. You might need to search for your printer if it’s not auto-detected.
After installing those RPMs, if it’s successful, and if it’s not autodetected, then adding would look something like this, in GNOME, in the printer part of system settings:
If it doesn’t have the right driver but it does see your printer, then you’d change it like this:
(Select printer details from the printer’s menu, if the printer is in your list. You’d first have to “unlock” the page with your password.)
On the details page, you’d click “select from database…”
And you’d see a dialog with printer drivers. This one doesn’t have your printer shown, but if installing the RPM with
rpm-ostree install (and the RPM files) was successful, after a reboot, then you should see your printer on the list.
(Note: If your printer is detected and set up properly by default after installing the RPMs and rebooting, then you wouldn’t even have to do the above steps.)
Sorry I can’t help any further.
If this doesn’t work, then you might need to use Fedora Workstation instead, if you want your printer to work. Or install an OS in a VM and print from that. Neither are ideal (reinstalling or using a VM for printing). Hopefully the
rpm-ostree install method with RPMs will work for you.
Also: Please come back to the forum to share with us if this was successful or even if it was not. Thanks! Best of luck!