The ampersand method in the OP video (and the sibling slipped-lapp-knot comment) is needlessly complicated. Just follow this super simple animation instead (except pass a bight in the last step to make it quick-release).
The Lapp knot (aka. lapp bend) is my favourite of all the knots and very underrated. It's so versatile and simple, even simpler to tie than a square knot. As shown in the OP, it can be tightened and loosened and explodes when you pull the tag rather than leaving the half-knot behind. It is my default way to tie two ropes together.