The biggeat flaw in your video is your choice of shape from 3 to 4. An easy roll gives you the 4 in the corner with built in shape for the 5. Your choice had you travelling a longer distance, across the shot line of the 4, into a way smaller window, and then required a great positional shot to the 5 with a huge 8ball to avoid. Fixing stuff like that will improve your runout percentage much more than technique tweaks imo.
That said, finding an instructor that will tweak your stroke rather than overhaul it and then just listening to him/her can be of much more help than some hodgepodge of internet advice from a variety of folks with good intentions who may all be working with a different idea of what an ideal stroke is.
Take grip for example.... some instructors like a snug grip like you have, some like the hand to open and close, some even like it so loose it has a gap between hand and cue....which others call slop. Weirdest part is that they are all right and their methodology has worked for countless players. But each part of the setup affects all others so u simply cannot mix and match bits of advice from multiple sources, even very reliable ones. I'd say, find an instructor who already prefers a snug grip like you prefer and then trust that person and only that person for a while.