How to wash a pure cotton t-shirt that won't age during T-shirt customization?

How to wash pure cotton T-shirts while keeping them old in blank T-shirt customization? After multiple washes, the color of the T-shirt has become very outdated, presenting some exquisite velvet that looks very outdated. How can I adhere to the color and texture of a T-shirt?
The main characteristics of customized pure cotton T-shirts are breathability, sweat absorption, and harmless to the human body. Cotton has good dyeing performance, and colored cotton T-shirts may fade slightly. Dark contrast is significant. When washing, it should be separated from other T-shirts, and the soaking time should be unexpectedly long. Mix the pure cotton cleaner and solution well, then soak the T-shirt, otherwise the T-shirt will fade unevenly.
Summer T-shirts are relatively thin, and pure cotton doesn't have very good crease resistance. Wash at a water temperature of 30-35 degrees Celsius and soak for a few minutes, but the time should not be too long. After washing, it is not advisable to wring it dry. Cool down in a well ventilated and cool place. Don't expose them to sunlight to avoid fading.
Therefore, it is recommended to use acidic washing products (such as soap) to neutralize them. If you use pure cotton detergent, it will be very good. Other summer clothes are often cleaned and replaced (usually every three days), so that sweat does not stay on the clothes for too long. Most T-shirts are custom-made with a single collar and are very thin. When cleaning, avoid using brushes or rubbing vigorously. After drying, tidy the body and collar. Avoid warping. When customizing a T-shirt, the collar cannot be wiped horizontally. After cleaning, do not wring dry, dry directly. Do not expose it to sunlight or high temperatures.