1. The CEO made terrible decisions in regards to how much and who they raised from. They got in over their hands as the company grew and the entire founding team got fired.
2. The CEO immediately after, who took over an unprofitable business that wasn't growing and was in bad shape after the merger with DraftKings got called off, took a deal that was the best he could do at the time. That CEO was a non-founding CFO before taking over, and was basically put in the C-Suite by KKR as a term of their investment in the business.
3. That deal to PaddyPowerBetfair, now Flutter, was completed about a year before PASPA was repealed and sports betting was legalized in the US. Had #2 happened a year later, or if #2 had happened with that information in mind, the deal terms would have been insanely different and way more valuable.
It's very easy in retrospect to say that the original CEO should have taken different terms, or that the following CEO should have taken a better deal. That's all hindsight.
All that said, I have zero sympathy for the original CEO and founders. I feel loads of sympathy for the employees, but again, if they stayed on after the deal, they're now sitting on an absolute gusher of cash.