That seems like a really bad idea. I don't know how prevalent level IV armour is, but if it becomes standard issue then the opposing force is going to be hosed if all they have to defeat it are 20mm grenades. What's wrong with going back to 7.62mm or exploring 6.5+mm ammunition?I think a key rationale for the QTS11 is to counter ever advancing body armour.
The US is looking at 6.5/6.8 and higher cal rounds to counter Russian and Chinese lvl4 equivalent plate. That adds significant weight in weapon and ammo.
China has show little sign that it is interest in such ‘overmatch’ calibers, and instead is playing with the QTS11 and smart grenades.
The long barrel and high pressure especially means the smart grenade probably shoots pretty flat, so I can easily see them using those for direct fire and HEAT like rounds to penetrate plate with explosive jets on impact.
The corner shooting ability with scope and eyepiece also seems like a direct counter to the suppression fire centric infantry tactic US and NATO forces prefer.