I thought that's an ZX-81 Spectrum but I watched it again and found out that it was not!

Edit: Watched again and it is an ATARI laptop because the brand showed up in a few frames. This is probably the one: https://en.wikipedia.org/wiki/Atari_Portfolio

A screenshot I just made: https://imgur.com/6I34YyN

You are correct, sir. See the link bluedino posted!