I find it funny that I discovered this seed before but I used a Survival build instead of a Brutality one (you know, because the second 5bc Hand of the King fight). I then realized how good the seed was and I just murdered the entire spoiler biome and the boss.
fyi if u use wish to make it legendary u get x3 dmg also u can get dammed modification from the lady at the beggning to get x2 dmg when cursed and deal almost 7million
I found a good seed while playing in 5bc, it is 220706. Had 3-4 challenge rifts (prisoner's quarters, Toxic sewers, cursed prison, Ramparts) you could look around more if you're interested but this is a pretty awesome seed I found on my own
I also found a similar seed like almost constantly it had challenge rifts in every biome up to slumbering sanctuary but didn't have any cursed chest because I wasn't using damned