It's the day for unlocking, mine was done today.This is how I put it to them.
"Hi. I have just bought a £1400 Galaxy S23 ultra.
I would like to unlock the bootloader....but the toggle is missing from Developer Options.
This is because it is locked using KnoxGuard.
I would like this lock to be lifted, so that I can unlock my bootloader.
Please remove KnoxGuard (active) from my device.
The details of my phone are below.
Red S23Ultra, 512\12gb.
S918B\DS"
They immediately understood what I wanted.