Comment 5 for bug 1945687

> I notice your /run directory is mounted as a temp filesystem

that's normal, /run is a tmpfs on everyone's system

> Detected unsafe path transition / → /run during canonicalization of /run.

This means that the owner of your / and /run directories aren't the same, and more specifically that your / directory is probably not owned by root, can you check that? If so that is very likely the reason that systemd-tmpfiles didn't create the /run dir that php was expecting to use.