initramfs suggestions for replacing console=null are not enough

The initramfs (via init_functions.sh:setup_log()) suggests replacing console=null in the kernel cmdline with quiet or silent. I don't see a silent param listed here: https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html

The description for quiet says it disables most logging. On my x13s, I still see some stuff awkwardly printed between/over pbsplash sometimes during boot when using quiet, and no messages at all from the kernel when using console=null.

What types of kernel messages make it past quiet, and is there some way to disable those without resorting to console=null again?

Silent boot

WIP list of kernel cmdline options that make boot quieter:

# note: order of quiet and loglevel matters!
quiet loglevel=2 udev.log_level=2