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 Hive Scum Build - Warhammer 40k: Darktide 

My build for pretty much everything

Sticky Fingers lets you spray on the move with enough precision to deal with gunners from medium range, and also allows you to brace+crouch and tap fire snipers from absurd distances. You'll be swapping a lot even during desperado to take advantage of the sprint speed + knife heavy run, so you get a lot of value out of this node.

Jittery allows you to dance in hordes with impunity. Despite this playstyle, I found I had really bad uptime anyways with Float Like a Butterfly (usually about 2:33min across a 22 minute run) which wasn't worth the point.

Speedloader gives you just enough reload speed to keep the mags chugging without dropping death+fire

I take the extra CDR talent for desperado because it is about 11% CDR, and more uptime is more time to tear into hordes or have it handy for gunner surprises/revives in gunfire/sprint speed with knife out. This lets you use the ability extremely liberally, which means sometimes you're not even going to shoot after you pop it. If you swap anything out in the build, this is the point you look at removing first.

I prefer the rocket launcher over the chem grenade because the way these 2 blitzes play out is chem grenade blows up hordes and light elites so you can focus on the armor whereas the rockets blow up the armor so you can go back to blasting hordes/light elites. The huge walls of armor tend to be most public game points of failure, so a quick rocket to solve that has helped me personally, but the choice here is ultimately up to preference.

Weapons: 

Agri Brauto has the same dmg per mag as the graia, which is the rate of fire mark everyone thinks of when they think about trying braced autoguns. The cleave on the agri is what makes it so lethal, you can blow away entire screens in a few bullets and cut through chaff to hit the sniper/trapper/dog reliably. Power on stim + deathspitter gives you more punchthrough, and we take crit stim because this weapon scales extremely well with crit against all targets. You'll be overcapped on rending against everything except carapace anyways  as soon as you hit desperado.

The knife is a mobility stat-stick that can also deal with a couple crushers at a time, or swipe up on bosses a bit to get some constant dps while you wait for a horde to appear so you can ramp your gun up and finish blasting it to pieces. If you want more single target instead, take precognition in the place of bleed.

Curios:

3hp lets you take another swing before going down, max toughness because you have the least DR of any class by far, and I prefer to have ability up as much as possible. Revive speed is the next most effective perk to take as it helps out your team a ton during the critical points of failure in a run.

Stim Lab:

Agri crits effectively add ~25% dmg to whatever you're shooting, which is basically like adding another perk (stacking with flak maniac so these guys vaporize). Finesse would be nice if our accuracy could get even tighter and we could more easily guarantee headshots, but that's not how these guns play. Rending is pointless with desperado and not worth investing into even if you want to shoot at crushers. You get your first biggest power-spike against them with a crit (5x dmg vs base) and then attack speed + blessings are going to scale you harder vs rending node.

As for taking a second path, 2 slots into attack speed has been my sweet-zone to take it into all levels of play without thinking about it, you'll have an easier time maintaining dependency with 2 full paths in higher havocs due to density. You only need 41 kills while it's on cooldown to get it back in time to use before your stack falls off. If you're having issues or don't want to manage it at all, just leave it on 1 path 50% viscosity and spam it as much as possible. There is merit on just having better overall uptime on your stim!