BF6 NEEDS RIOT SHIELDS

I don't think the army even uses riot shields in actual armed combat? Riot shields are mostly used by police units to, as the name suggests, deal with riots. They are mostly meant to protect from melee attacks and things that people throw. They aren't designed to stop bullets.

Ballistic shields on the other hand would be a better fit, but it's really a specialized tool. I can imagine military units would use it in specific defensive or breaching scenarios, but when you need to be mobile and travel long distances, carrying a relatively heavy shield around isn't going to do you any good.