These are literally Pillagers or other raiders but they wear armor
The only Pillagers that could spawn with armor are ones in the 4th wave and up in raids or at an outpost. But, in hard mode, pillagers wear armor in the 2nd and 3rd wave. Vindicators can wear armor too but that is really overpowered considering their damage so it will only be possible in creative mode. You should also be able to swap the vindicators Axe for something else in creative mode. The same goes for witches but they will not spawn naturally in armor.
Villagers can already wear armor but it would be nice if you could actually see them wearing it