Blitz Arby
 Arbites Build - Warhammer 40k: Darktide 

Hold your shield up to command your dog and line up headshots, even while under fire from gunners and the like.
Shield-Flash counts as blocking while you charge it and has a surprisingly large 20m range.

Break The Line counts as blocking while it executes, and should be spammed with how low the cooldown is between Curios, Targeted Brutality, and Malocator.
Pushing counts as blocking and needs to be done regularly to maintain Drive them Back.
Notably, both of these inherit your shield's ability to block ranged attacks.

Shield Plates makes clutching and tanking bosses much easier, and gets a surprising amount of uptime with all of the above considered.
Walk it Off would be amazing if there were points for it, but isn't worth the sacrifice IMO.

Switch Auras as you see fit.
Plenty of the dead-end nodes are eligible for sacrificing to pick up Rebreather when modifiers call for it, just take your pick.

Your standard rotation to maintain both Drive them Back and Weight of the Lex:
Push > Attack > Light > Heavy > Light [> Heavy > Light]

The opening Push > Attack > Light is all executable with a single click so long as you hold it and release at the right time.

You can also neglect the timed release and just hold for a heavy to go straight into the strikedown rotation instead of the clearing rotation, which is a very nice way to focus down high-priority targets in a mixed horde:
Push > Attack > Heavy > Light > Heavy [> Light > Heavy]

Go for headshots with the Revolver. This setup one or two-shots every elite and special rather comfortably, even without a damage buff or two, crits allowing.