Someone who can deadlift 200 kg might be able to do it in a less efficient way. Holding the position you want in a lift, the same position that often feels natural with lighter weights, usually becomes harder as the weight increases. A lifter who has developed an efficient movement pattern often has a physical 1RM that is very close to their technical 1RM. Others may have a much larger gap between the two.
If we use a 200 kg deadlift as an example, a technically efficient lifter may be able to maintain their position and execution almost all the way up, with the technique only starting to break down around 190 kg. Someone with less technical control might be able to hold a good position up to 50 to 100 kg, but after that their technique gradually starts to deteriorate.
Two people can therefore both have a physical 1RM of 200 kg, while one of them also has a technical 1RM of 200 kg, and the other may only have a technical 1RM of 150 kg.
If both of these people follow a training program based on a 200 kg max, their training will produce different results. The lifter whose technical and physical 1RM are closely aligned will develop technique and strength more or less in parallel. The lifter whose technical 1RM is 150 kg but physical 1RM is 200 kg will instead continue reinforcing inefficient technique and in some cases may even make it worse.
This assumes that the lifter is not actively working to improve their technique regardless of the weight being used.
If you are someone who has a large gap between your technical and physical 1RM, it is often a good idea to base your training on your technical 1RM rather than your physical 1RM. This does not necessarily mean you must go all the way down to 150 kg if you can deadlift 200 kg, but your training weights should probably be much closer to 150 than to 200.
The reason is simple. Once the load exceeds what you can lift with good technique, the quality of the stimulus decreases. Repetitions performed the way you want the lift to look will stimulate both motor patterns and muscles better than repetitions performed with compromised technique.
An effective way to improve technique is therefore to train with weights that may sometimes feel almost too light. These lighter loads allow you to get into the right position, maintain that position throughout the lift, and repeatedly practice the correct movement pattern.
From there, the load can gradually be increased little by little so that the majority of repetitions remain within the technical standard you want the lift to have.