I like this build it is fun. (laspistol greatsword all-rounder psyker)
 Psyker Build - Warhammer 40k: Darktide 

I bind Scrier's Gaze to spacebar just for peace of mind lol. 

You can swap flak armored on greatsword with maniac if you hate ragers and muties more. I run flak mainly for the new annoying vanguard shield enemies lmao. Las with unyielding and a combat/celerity stim melts bosses like icecreams. This build is pretty flexible so play around and see what works for you! 

For the tree I run Quietude and Perilous Combustion to soften up gunner groups with soulblaze and proc Kinetic Flayer to help with said new annoying vanguard shield enemies but you can swap them with: Just a Dream / Ranged Damage Boost or Charged Strike + Enfeeble to 1-2 tap heavy crushers easier and empower  Smite if you want to use that instead of Brain Rupture + Kinetic Flayer . With Scrier's Gaze you have a ton of Smite you can use in emergency situations for repositioning, breathing room, and revives. You are very fast with the laspistol and the push attack can stop bursters from a distance without the risk. Spamming greatsword's push with Scrier's Gaze is also amazing for opening up bullwarks and getting out of swarms. 

This build can work with both Smite  or Brain Rupture + Kinetic Flayer for more dps as it works well with soulblaze. I do find Smite more useful for pubs though, especially if teammates go down and you're not communicating via vc. A pause button for revives goes a long way. 

This build is pretty chill and solid for hi intensity aurics, maelstroms, expeditions, and mortis trials. I wouldn't recommend it for high havoc with randos (inferno staff out-dps's sword for the most part) unless you have teammates to communicate with or running med abilities like golden toughness smoke or bubble though. 

Highly recommend the following mods for this build:

• Fullauto (helps prevent carpal tunnel with las)
• Danger Zones (helps you see burster aoe, fire on the ground, and daemonhost agro range)
• Crosshair Remap (for greatsword crosshair to better hit headshots) 
• Enemies Improved (provides color-coded highlights and healthbars. i can barely see enemies without it, not a fan of this game's enemy design language compared to vermintide's)
• Warp Unbound Timer (helps prevent accidentally blowing yourself up lol)
• Custom Hud (mainly to place your toughness bar smack dab in the middle of your screen. you want your toughness to always be 100% to eat free melee hits)
• Show Remaining Dodges (pretty essential if you're not running Warp Ghost)
• Quick-Chat to communicate dropped ammo/medkits or custom bindable chat messages. 
• Extended Weapon Customization_owo (the silencer for laspistol is really cool and i adore the customization options!)