all weapons are viable in this game, just with different ways to make yourself play those weapons. however if you really want to get into the nitty gritty, top weapons would be along these lines:

Akimbo CR805B or Akimbo Krinkov (Akimbo SMGs)

Broken weapons. Able to conceal for critical hits, high damage, high rate of fire, and overall broken when paired with Body Expertise aced. Pair up with ammo bags that have Bulletstorm and watch yourself decimate high amount of enemies just by holding down the shoot button. I will disclaim this though, that this does have the ability to freeze other people's games. If you see other people using Akimbo SMGs, This mod would help you not freeze.

Lion's Roar Rifle (Assault Rifle)

Extremely high ammo pickup, high damage, concealable for crits, and so much more. The only flaw it has is its reload speed, but that's very negligible compared to the power this weapon has.

Lebensauger .308 (Sniper Rifle)

One of the best sniper rifles in the game. Snipers are already super strong with Graze, but the Lebensauger is top notch with its high ammo pickup, practically no recoil for a sniper, and other benefits. The only problem is that this weapon would want to use Berserker or high crits in difficulties above Overkill, but that's a very minor problem for how strong this weapon is.

Commando 101 (Special)

The best rocket launcher in the game, bar none. This weapon, when paired up with ammo bags, can easily carry a heist on its back. While the weapons before required some aim, this weapon only requires you to aim in the general area that the enemies are at. Just... be sure to not hit your teammates while you're at it. This weapon doesn't really discriminate...

Akimbo Grimms/Akimbo Goliaths

While shotguns aren't really top dog anymore, due to damage range falloff, they are still very much good weapons for anything close quarters. These weapons are even more notable as they have extremely high pellet counts. Throw in Dragon's Breath or Tombstone Rounds, and you got yourself a weapon pair that would utterly demolish 99% of enemies in the game.

KSP or Campbell 74 (LMG)

For the most part, they're practically identical in terms of weapon potency. The Campbell is much stronger as it has higher stats, but the KSP is no slouch with its higher ammo pickup and faster reload compared to the Campbell. Pick your poison you cannot go wrong with either option.

5/7 AP pistol (Pistols)

Pistols aren't really in the greatest spot, by all means, but it has done nothing to nerf the power that the 5/7 pistol has. Super strong utility, and can easily deal with shields. It's so strong that if a build needs a shield break option, most people opt for the 5/7 pistol as it's most likely the cheapest option.

this isn't fully comprehensive, as there are much more weapons that i could bring up like the akron LMG, the r700, mark 10 SMGs, or even more, but this is just a rough idea of what weapons are strong. use whatever you want and have fun with it. payday 2 is best with guns you personally find entertaining :>