I belt over 325 lbs usually now, occasionally going to 345 without after some @happyscrappyheropup advice. Over 345 though, always belted
To preserve my knees I no longer go below parallel to ground with anything heavy.
One of my favorite squat exercises is setting the safety bars even with my parallel (or slightly below), letting the bar rest there, and starting from the bottom. Not having that tension loaded makes the lift more difficult, but it really impacts my ability to explode back up on traditional squat lifts