This is a monitor with Variable refresh rate
I changed 60 Hz - 165 Hz in Cinnamon System Settings -> Screen.
But I feel it when I turn on the computer, because it changes from the default 60 Hz in the bios/systemd-boot/console to my system 165 Hz. So the startup animation of the transition from the black screen to the Cinnamon desktop does not happen at all before my eyes, because the monitor is still switching the refresh rate (the resolution remains as it should be in the bios/systemd-boot/console).
And when switching between TTY Ctrl+Alt+F2 etc. the same thing, it takes that long and in the background the TTY is already ready.
I dream of setting 165 Hz in the bios/systemd-boot/console.
But in DisplayPort, even setting the system to 60 Hz does not help, something changes anyway.