Melee Psyker (post DoTD)
 Psyker Build - Warhammer 40k: Darktide 

Mostly from basic testing as I am still practicing a melee playstyle, but have found this the most fun so far. 

Basing it on the BFGS, using the MK6 has an easier time striking weakspots with the overhead attack pattern, aswell as stab attack. Using Unstable Power and Shred as a start, but Riposte can synergize better especially when picking Anticipation as a talent, however I do think there is some leeway as you could also use Blazing Spirit instead of UP. 

The MK2 Laspistol is very nice for extra mobility when sliding around between areas, and this mark also allows for quick applying Infernus stacks before closing in on a target (also for free procs of Kinetic Flayer when needed); will note that I can see use for the MK10 aswell, but I would not run Infernus on it and would pick something else. The secondary isn't as particularly important, as I find it more useful to use it for utility rather than basing this build around gun usage. 

Curios are pretty standard, but I do see use for adding a damage resist option or ally revive speed instead of stamina regen.

As for talents, the idea of speccing into Soulblaze really helps with maintaining Empathic Evasion, aswell as free toughness regen from killing enemies with it. I find that once you get past your Aura, you can spec into Immaterial Focus instead of Anticipation, but you still very much need EE and the Soulblaze nodes (everything else I would say is standard for a BFGS centered build), while anything past Scryers can be up to preference (i.e. Kinetic Deflection over Peril Equilibrium, I use Solidity to help maintain decently high peril consistently but I can see not using that and speccing somewhere else). Disrupt Destiny into Lingering Influence is the best way to go, but will add that any extra point into Cruel Fortune can't hurt, generally depends on preferred playstyle but this is what works for me in Auric lobbies.

I will also add that not going for DoT can also be viable, but there I would definitely suggest both Gunner Resist on curios and being more mindful of staying close to your team to avoid being singled out and getting shot out back by gunner packs. You can use the extra points into Keystone/Ability mods or extra points somewhere else (like dipping into previous nodes mentioned.)