You're talking two different applications here if you're looking for dedicated uppers.
An entry gun usually is very compact and lightweight and sometimes full auto as you're usually weighted down with enough crap on you to sink in damp mud! Pinpoint accuracy is not necessary as your shots tend to be under 50 feet or so (usually quite a bit less).
OTOH a dedicated CS upper is usually a heavy barrel or bull barrel unit with a tight chamber. Also with a full stock or adjustable aftermarket stock and a free floated forearm. Built for accuracy and not speed. Most units depend on a bolt rifle for this application though in the typical LEO scenario (distance-wise) a semi-auto could have some advantages.
Even the ammo requirements may be different for each application. The CS firearm may use 62 gr (if .223) with a 1:9 or slower twist barrel while the entry team may use a frangible (Hornady TAP) or 55 gr bullets with a 1:7 twist barrel so that penetration is not as much an issue.
If you absolutely must have only one upper, you'd probably be better off with a 20 inch HBAR flattop and confine your CS work to ranges at which you have absolute confidence in shot placement in all conditions.
