You should be able to check each motor with the PROPS OFF in the motor tab in Betaflight, if each one in turn works when you operate the tabs one at a time then the motors and ESC’s are OK, since you are operating them without the FC. That leaves you with a set up problem not hardware.
Did you backup the whole standard configuration before you changed anything? If so then you can try resetting to the as supplied configuration and then see if it’s still doing the same thing.
Sorry if I missed something in your video, I can’t watch it at present so this reply contains some guess work.