Disabling plymouth on a fresh Fedora 31 installation reduces the boot time by about 50 percent over all tested systems, using a Desktop PC (+ Nvidia), a T495 and a T440p.
The test involves:
systemd-analyze plot > boot.svg
rd.plymouth=0 plymouth.enable=0 to kernel boot parameters
3.) Re-generating grub
If you have a fairly fresh installation (to make it reproduceable) please test this yourself. I’d love to hear if this applies to all setups, and is realted to plymouth, or only applies to my set of hardware.
I’ve created a bug report, but it has not been gaining traction yet.