I got 1000s+ from being idle and hired 2 heroes. I leveled up heroes about by a few hundred levels or so, and within 1 frame the monsters died.
I had progression mode on when said moment happened. Even the first boss I got to died within one frame. But the boss at level 95 wasn't like that, unfortunately. Amenhotep has gotten to over level 150, so I can ascend now. Cid has gotten past level 600. Treebeast has gotten to over 500.
I can almost kill Omeet on Bloodlands Level 100. But I can't completely, though. Quite unfortunate. My total levels from heroes is over 8,000. That means if I ascend now I will get 4 hero souls.