I have no idea about the waist, but I think I half the know the shoulders bit! I THINK you need to focus on the rear and side parts of your deltoid muscle. Not 100% what excercises do this though! But hopefully it gives you a starting point you can go to google from!
After being a big fan of her on social media for several years, I'm excited to finally pick up a (kindle) copy of Dr Victoria Taylor's (@spitfirefilly.bsky.social ) book, Eagle Days! Looking forward to diving into it!