Need build advice with mercenary.

Hello, fellow exiles. I've started this season a bit more than a month ago as mercenary. Levelled as permafrost wh, but specced onto tactician buff stacker after some dozens deaths on arbiter of ash. Managed to kill first arbiter of divinity and finish all secondary atlas trees except delirium. My dps seems to be ok, but tactitian feels squishy af. I've burned out, tired of dying. Spent 50 divines on Disciple of Varashta and finally i can play freely - for this modest price i've finished atlas and got capable to run t15*6 maps with 3 tablets (without delirium for now). Only for 4 days with varashta i've managed to farm about 200 divines - more than in a month of suffering with mercenary. I know i'm bad at the game, but this is my first endgame league and i'm learning. Now i'm thinking of returning to mercenary - i adore this alien shooter-like gameplay. Is there any crossbow based builds you can advice? Any merc ascension. I'm not sure there is any way to make tactician tanky enough, so i lean to galvanic shards/stormblast bolts wh. If there is a way to make tactician better - i'll consider this too. I can farm a couple of hundreds of divines more, maybe even for mageblood or rakiata, but i don't think it will solve my problems. Ninja here

Need to add, i play on a potato pc, so glass cannons works only before maps juicing, i need something tanky enough to survive fps drops.