Fitz's Nu Patch H40 Psyk - Melee Pskytzo
 Psyker Build - Warhammer 40k: Darktide 

They killed gun psyker with the inexplicable removal of Tranquility Through Slaughter (Non-Warp Ranged Critical Hits Quell 4% Peril), but thanks to the new efficiency in the tree, we get to use soulblaze items more easily, so this is my current proposal for melee psyker. Duelling Sword is equally, if not more valid, thanks to how soulblaze will interact with Uncanny Strikes.

The Laspistols have unique pushes with practically infinite cleave, allowing you to push bursters through blobs of Crushers, but keep in mind that this generates 10% peril, so you can headpop if you use it at 100%. They're good enough to also snipe specialists and gunners thanks to dumdum and infernus. You CAN run a staff with this and the most likely candidate would be the Electrokinetic (EK) staff, but you'd probably be better off using a more specialized build for that instead.

As for blitzes, I believe in Kinetic Flayer for speeding up elite kills every once in a while, but it has its detractors.  Assail would be there primarily to proc Malefic Momentum if your melee weapon ISN'T a Force Greatsword (i.e. if you prefer the Duelling Sword instead), while you could also theoretically run Smite with Charged Strike, but it seems the worst option of the three.