How do I enable `SysRq` on Fedora Silverblue?

Unfortunately my system has been hanging quite a lot lately, which isn’t great. I’d like some more options to recover from that, and so I’d like to enable the magic SysRq key. There are instructions on how to enable it in Fedora (e.g. here), but they involve modifying files that are read-only on Silverblue.

Is there a not-too-fragile way of enabling it on Silverblue?

Files in /etc are writable on Silverbue.

Oh! Pfft, turns “can’t open the file for writing” is because the directory didn’t exist yet. Thanks!