Most research on resistance-trained individuals lands in a similar range: somewhere around 1.6 to 2.2 grams of protein per kilogram of bodyweight per day supports muscle repair and growth without meaningful extra benefit beyond that point.
That's a wide range on purpose. Where you fall in it depends on how much you're training, how aggressive a calorie deficit you're in (protein needs go up when you're cutting, to protect muscle), and your starting point. A coach adjusts this based on your logs, not a flat formula handed out on day one.
You don't need a protein shake after every workout to hit these numbers. Whole food sources — eggs, dairy, poultry, fish, legumes — work just as well as supplements. Shakes are a convenience tool, not a requirement.
More isn't automatically better. Past roughly 2.2g/kg, additional protein mostly displaces other nutrients without adding extra muscle-building benefit. The goal is hitting a consistent target daily, not maximizing it.