I had the same issue. If you create a file like /etc/sysctl.d/z-10-fix-traffic.conf, sysctl will overwrite the setting correctly. You can see the order files are read with sysctl --system command:
* Applying /usr/lib/sysctl.d/10-pve-ct-inotify-limits.conf ...
* Applying...
I had the same issue on our cluster with ceph suddenly showing slow ops for the nvme drives. ceph was already on Pacific. Nothing hardware wise changed on the servers and it affected random drives. But the regular SSDs had no issues. I checked the apt logs and for me the issues started once...