Hi @label1 ,
Please add a timestamp to show where in the video, Kent Bakes Displacement in Cycles, without using Multires. As far as I know, Displacement Baking in Cycles has always only been possible via Multires.
You should always Apply the Scale, when you forgot and try to do it later, some things might behave unexpectedly, like when you have a Bevel Modifier and then Apply the Scale, the Bevel might be a lot larger or smaller than before…all sorts of things can go wrong, impossible to tell what exactly you did wrong.