HELP! Tainted Crafting challenge in SSF

Hello,

I tried to complete the Tainted Crafting challenge several times in SSF but I am not able to get a rare Tainted currency.
My strategy until now:
- All of the Beyond Atlas nodes allocated
- Elder and Shaper influenced maps to increase density
- Eater of Worlds influence for additional packs
- Rolling Beyond as map mod
- Using Delirium orbs
- Sextants that increase monster density
- Scarabs that increase monster density (Strongbox, Harbinger, Abyss, Legion, Breach)
- Map Device options that increase monster density (Legion, Strongbox and Abyss)

With this strategy I can reliably find a Beyond boss each map but until now I haven't been able to get a Tainted Chaos, Tainted Exalted or Tainted Divine Drop.
Is there anything else or anything different I should do?

look up price of said currency in trade league, make a new character.

get the item to use it on and the currency + some extra and go to trade league with it.

buy it, complete it.

otherwise just keep trying, eventually a tainted ex/chaos will drop.

It would feel like cheating... I will keep trying with the juiced maps

I'm playing with Grand Design allocated, no sextants, no beyond nodes, no kirac mods and no special re-rolls on maps to get beyond, and completed the challenge without buying tainted currency, in ~1500 maps. Still have a tainted chaos orb. Haven't seen a divine teardrop yet.

Probably it's easier to get tainted currency by running the league mechanic - each Beyond node guarantees a Beyond boss, which drops tainted currency.

got a couple of tainted mythics from the lake scourge tiles