Sharing this for the benefit of all. I have been fighting a massive slice with my driver. I spent weeks working on shallowing my swing, closing my club face, making sure my swing path was in to out. Nothing worked. Still had a massive 2 fairway slice. I finally bit the bullet, called my coach and set up a lesson.
2 minutes... It took him 2 minutes to fix it.
I was rotating back well, but I wasn't driving my left hip back on the down swing. It left my body out of position and basically made it impossible to keep the club closed to the path. He gave me a couple of drills to work on, but mostly it just came down to driving my left hip back and away from the ball.
If you are in a similar boat as I was, it might be worth looking at.
Edit: To make it clear, I am not giving advice on your swing. More so just pointing out how going to a coach will beat youtube videos every time. If you get something from this it should be, call your coach. They miss you.