Well, dual-wielding means using both hands at the same time, so you exponentially decrease the effectiveness of each hand because the brain is trying to compensate. Ever see a picture of a guy dual-wielding airsoft? Usually one gun is pointed at the back of his buddies head and the other is off in left-field, neither aimed at his target and his face looks like he's having a stroke, or consentrating too hard and can't understand why no one is calling their hits. A single pistol is vet effective CQB because of how low-pro it is, you can practice properly switching hands and often use your other hand as support. Most tactical pistol shooters use two hands while firing their sidearms, it helps with stability and focus. The action movie single arm straight out/full one-handing, dual wielding, or cowboy style is not at all effective. Now take away the accuracy of a bullet vs a BB and it's worse. Carry two pistols if you wish, but run them one at a time.
There's plenty of threads on here about sniper rifles, in fact there's a good one at the top of this newbie section in the stickies. You mentioned how unwieldy a rifle is versus a pistol in CQB? Well, extrapolate that for a sniper rifle. Now remember that they are bolt action, so that's one round per bolt pull. The BB physics also don't change, so it being a sniper rifle doesn't mean it shoots more accurately and it shooting harder doesn't mean more distance. Sniper rifles can be fun in some settings, but they don't work like in the movies and take a lot of money, upgrades and modding to become effective. My M4 CQB outshoots most sniper rifles on the field and at a lower FPS. If you fire and miss, another player will be on you with consistent shots, more volume, easier moving and aiming, and more round in the mag.
Take heart though, as your misconceptions are very common among newer players. My recommendation is to get a solid rifle and pistol, half of which you already have, and then branch out from there. That way you always have the reliable and effective guns to fall back on. But your bread and butter is a good AR and a good 9mm. Sometimes you have to choose; cool factor, or ass kicker? Often if done properly they can be the same thing.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē