John Darktide Plasma
 Veteran Build - Warhammer 40k: Darktide 

Basic Plasma Vet build

Dueling Sword perks/blessings: 
 - Crit chance perk is optional. I like running it for just a *bit* more consistency, but you can easily run Unyielding or Flak damage instead. If you find yourself fighting bosses more often, take Unyielding. If bosses are usually covered by teammates, Flak is much better.
 - Thrust is what I usually take for more boss damage and one-tapping mutants, but it can be swapped to Uncanny Strike, Agile or Precognition. I like Precog for the consistent damage output you get against *everything*, but you would want Uncanny Strike if you're killing armour more than anything else. Agile is amazing for controlling hordes and staying mobile in high-pressure situations, but it is objectively worse than the other options- take this if you often find yourself fighting large hordes alone.

Plasma Gun perks/blessings:
 - If you prefer shooting crushers, you can swap Unyielding for Carapace damage, but if you do, make sure you adjust your dueling sword accordingly. You shouldn't have both weapons dealing with the same damage type. 

- Curios -
Combat ability regen is required, anything else is going to be worse.
Stamina regen is not required, but I highly recommend it and it's difficult to make a case for anything else.
Toughness is flexible. The talent tree I have doesn't really need the extra toughness because you already have a *ton* of it. Alternatives would be a combination of sprint efficiency and/or block efficiency. 

- Talent tree -
You basically only have two flex points here: (Bring it Down! and +25 Toughness boost)
One point should go into Always Prepared and the second point should go into Field Improvisation*. You can also consider Longshot or Kill Zone over Field Improv, but that's more down to your preference and skill level. High skill players should be selfish here and focus on giving themselves more damage.

If you don't take the +25 Toughness boost, I recommend running +5% Toughness on your curios to make up the difference.

*Note: This is assuming you're in a premade group. Field Improv is potentially useless when playing with other random Vets. I prefer Kill Zone or even On Your Toes when pubbing.

- How to play this build -
Pretty straightforward gameplay:

Dueling Sword light attacks for hordes and heavy attacks for elites/specialists. Stabbing crushers/bulwarks is much more efficient than shooting them with the plasma, especially when you can knock them down with your grenades.

Plasma for any elite/specialist you see or to help thin out mixed hordes. It can knock down larger enemies with a headshot and will pierce through some walls/doors/terrain.

With Weapons Specialist, you'll want to get used to swapping often and don't be afraid to dive into hordes with the dueling sword- it's quite good with the buff you get from ranged kills. Just remember to dodge often in order to utilize all of your buffs. 

You'll basically want to manage your plasma gun's heat the same way you would peril with a Psyker. If it gets too hot, swap back to melee for a bit while it cools. This allows you to maintain higher damage for more efficient shots.

Also, your shredder grenades actually count toward earning stacks of ranged specialist. Sometimes, you'll want to stay back and shoot elites while your team is fighting the horde and a couple of grenades can help builds stacks quickly, allowing you to stay at range with the full buff.

Spam your shredder grenades. You should always be at a maximum of one grenade at any given time, so don't hesitate to toss them when you have them. They're your chief means of clearing bigger hordes and they are excellent at knocking down large enemies for you and your team to finish off. Demo Team may not sound good on paper, but when playing higher difficulties with tons of elites/specialists, you'll get them back faster than you can throw them.