A 80Bronze 300W can still be more efficient than a 750W 80Platinum on mainly low loads. Additionally, some of the devices are way more efficient than they are certified for. A well known example is the Corsair RM550x (2021).

If your peak power draw is <200W, I would recommend an efficient <450W power supply.

Another aspect: Buying a 120 bucks power supply that is 1.2% more efficient than a 60 bucks one is just a waste of money.