I've now disabled systemd-oomd on my Fedora desktops

Systemd-oomd is a somewhat controversial systemd component that, to quote its manpage, "Uses cgroups-v2 and pressure stall information to monitor and take corrective action before an OOM occurs in the kernel space". Achievement unlocked: I just had systemd-oomd kill my entire X session for unclear reasons. If the configured limits are exceeded, systemd-oomd will select a cgroup to terminate, and send SIGKILL to all processes in it. Service template be enrolled in systemd-oomd, Fedora made the cgroup that systemd-oomd would select to be killed be all of your processes. Unlike the kernel OOM killer, systemd-oomd doesn't log any details and makes no attempt to identify which process, sub-cgroup, or whatever is actually causing problems. By contrast, the kernel OOM killer acts later but would have only killed a single process and in any case would have left copious information in the kernel logs. I would much rather have dealt with the kernel OOM killer in this case; even if it had freaked out and killed my entire session, I would know a lot more about what had gone wrong.