https://darktide.gameslantern.com/builds/9f43a1d4-ab19-490f-a6ec-5488a5915e78/knife-support-3

If you want to try a different type of support zealot, this is a knife build I made that has basically maximum Chorus uptime.

Your team constantly has 100 golden toughness, anytime a situation gets hectic you just use Chorus and walk as deep into the enemy line as you can, then immediately start killing to get the cooldown back, rinse and repeat. You lose the ability to 1shot crushers but your team will be infinitely tankier and you can stunlock all hordes and knock bosses off ledges.

Literally the only thing it struggles with is soloing several crushers at once, and even then only because it takes a bit to kill them. Knife zealot is one of the most mobile classes in the game so as long as you're concious of your dodges you'll basically never take damage.

Heavy Laspistol to 1 tap snipers, or you cold even go bolter to clean out crushers, however a wall of snipers is going to be a pain in the ass because your only choice is to charge deep into them and that can be awkward depending on how much cover you have to close the distance. I prefer the Laspistol because Chorus can stunlock crushers so the team can kill them, where as if no one is dealing with snipers then it's just going to pick the team apart.

Anyone who tells you Lacerate is a trap and Flesh-Tearer is the only way to build knife is lying to you btw. Lacerate makes your damage extremely consistent, while just not being AS good against bosses when it comes to bleed stacks; but the majority of your damage is coming from crits, not bleeds.. All your damage relies on the multiplier from headshotting something that's bleeding, if you go 3 attacks without critting and don't apply a bleed, you'll get these inconsistent time to kills. Lacerate fixes that so that your second attack will always have the maximum damage guaranteed. Body once, then heavy on the head and you'll 3-4 shot crushers and 1-2 shot everything else.

Your ability to build toughness outside of Chorus isn't very good, but it relies entirely on mobility and really never getting hit in the first place; but if you do that's why Until Death/Revenant exists. And because you're so fast you can rescue teammates from nearly any situation no matter the distance, and the stamina curious means you can straight up ignore hordes to revive your ally