It’s an individual thing. The point where someone reaches a strength level that can become traumatic for the body. And depending on how “solid/big” someone’s natural structure is, this strength level will vary.
I’ll give you some example among people I work with or know well.
I train an international level athlete who is extremely explosive (3.58 sec/30m, 40" vertical) and very strong for his size (505lbs x 7 on squats at 180lbs last week for example). But the guy has a very small structure… (5’6" with small bones, small joints). With the weights he can lift, the stress on his body is very large. YES he has the muscle strength and neurological efficiency to lift those weights BUT his skeletal structure and tendons are put under trememdous strain. So his training volume is very low, but he is still progressing.
We will keep pushing the squat until he hits 600lbs then we will stop training the back squat for strength altogheter because getting stronger on that lift will no longer contribute to improving his athletic performance and will pose an increasingly high risk of injury. So we will focus on increasing his power clean (it’s at 350lbs right now, he can likely reach 375-385 if we focus on it) and the front squat will become his main lower body lift because there will be less structural loading (he can do 450 right now, he can increase it to 500 without any added structural risks).
On the end of the spectrum, a friend of mine is Canada’s strongest man. JF was born on a farm, has super thick bones, thick tendons, built for physical work. Even though he competes in 15+ strongman competitions per year, he has never been seriously injured. Just an iron-tough body. He is a leanish 320-330 on 6’2" and he has the bone structure to support that.
Because of that he is capable of handling a very high volume of heavy lifting without breaking down.
So when you need to decrease volume, intensity or frequency you need to evaluate each individual and it is an art as much as it is a science. But provided that the lifter has good technique, rarely will this come before they can squat at least 2.5x their body weight, deadlift 2.75-3x their body weight and bench 2 - 2.25x their body weight.