Noctis, you tend to flinch away from string because you learnt that a good release is when your fingers are touching your shoulder at follow-through. And you are trying to do it as you were told. You did not developed your own follow through for arrow hand based on what you really feel in your hand the moment the arrow is released. Learning things is good, but at one point make those things yours.
Maybe the rush to touch the shoulder after release is forcing the fingers to have a 'guitar moment' on the string @ the release instead fingers pointing the arrow's direction while releasing. But these can't be seen in a video without falling in assumption trap. The best doctor for less obvious things is you. And you just gave yourself an answer: over-focusing with the form is preventing you to get the best from it. Give the brain a pause, feel the bow, arrow and your body instead.
PS For the elbow out, you don't need to force it to the point it feels unnatural. When you do push-ups on your fists on the wall the elbow is naturally oriented outward, right? Otherwise you couldn't do the push-up - or your hand will be parallel with your body. Look at your hand extended after the push-up. The fist is slightly rotated (knuckles oriented to a close to 45 degrees), the elbow is pointing out without hurting. Have the same feeling in the bow hand, nothing more.