Let me ask an unpopular question: in which sense did it "go badly"?

You indicated a large amount of technical debt and issues, which the techie in me 101% empathizes with and shares your pain. You also indicated morale and hiring practices issue, which the person in me empathises with.

What you didn't indicate however was the business outcomes: Were there unhappy clients that left? Did the costs rise? Business fold?

Everything you mentioned, unfortunately, is also the case for some wildly profitable/successful businesses.... :-<