You have the "broken inaccessible" crap in your "still fairly useful" crap around the 1:15 mark. You don't show your vertical or portrait handling at all since it's a fixed window, which is why I don't trust videos instead of actually having access to the app/page itself.

Your "interaction with zoom" borders on nonexist5ent, with many elements not scaling like the icons, which in all likelihood (educated guess) means it's useless crap for 4k users. "

I've seen all this before, and it's the same incompetent trash that min-width for the control elements, doing everything in EM/REM, and avoiding dicking around with excess calculations could easily provide solutions for without overthinking things.