My ITX box consists of an Asus X470-I, a Ryzen 3700X (used to run perfectly with a 2700X too), 16GB RAM, 3 SSDs, 1 mech HD, a 1080Ti and it's running perfectly from a 650 watt EVGA Supernova G3. Had to go with the 650w G3 for it to fit in the ITX case. The PSU never even gets hot even when the PC is under load which suggests it isn't really being stressed.
Definitely no real need for 750+ watt PSUs with relatively normal spec systems unless you have a board/other devices that need the additional connectors.