We recently uploaded a 6.14 kernel into our repositories. The current 6.8 kernel will stay the default on the Proxmox VE 8 series, the newly introduced 6.14 kernel is an option.
The 6.14 based kernel may be useful for some (especially newer)...
yeah, a short paragraph for the docs would probably be a good idea. note that this mainly affects existing containers - new unprivileged containers are created with nesting enabled by default for this reason (at least when created via the GUI).
you don't need to mask any services inside the container - simply enabling the "nesting" feature for the container (if it is unprivileged) will allow systemd to make use of its namespacing features.
Did you ever diagnose this problem? I'm experiencing the exact same symptoms. Running PVE 8.3, recently upgraded from PVE 6.4. I have just downgraded from the 6.11 to the 6.8 kernel to see if it makes any difference.
My network config is 4 NICs...