Max armor receivable is capped to 20(equivalent of full diamond armor)

Received armor for the player is somehow capped to 20 or the equivalent of full diamond/netherite. This is a bit of a problem for addon makers as they can't make armor sets that provides greater than 20 defense.

 

Expectation:

 Having for say, 30 defense should protect you better than 20 defense from a creeper explosion for example.

Observation:

 You take the same amount of damage even with 21+ defense as you would with only 20 defense

 

How to reproduce:

1. Make a custom armor item that gives you more than 20 defense or wait for me to provide you the custom item.
2. Take damage from something that deals a lot of damage(like creepers, vindicators, ravagers)
3. Do the same but with either full diamond or netherite armor
4. You somehow take the same amounts of damage