i can't find any bismuth bar

hi all i been playing 4 over a week now 10 days at leas i think but i have not find a single bismuth bar so far i find the other ore alot but not these one no matter what i need at least 10 bars to upgrade my town thing i have no idea what i should do i am in act 6 just start it from act 4 to act 6 and i spent alot of times lvling in act 4 and in act 5 and still can't find that stupid ore

Play through the campaign first.
You don't need to spend time leveling in acts. Just try to be the same level as the area.

Keep progressing your character. The rarity of ore only become available at a certain point. I'm not sure what the points are exactly, but i'm assuming you don't have Verusium yet either, because it only becomes available at a certain point, which I think is maps.

I think bismuth does spawn in the campaign, but it might be later on. Maybe act 7-8, I'm not sure exactly. It will spawn later on though.

Youll neet to find Bismuth ore and smelt it into bars in Kingsmarch.

Type of ore depend on your progress throught campain.