It's fun to think about. I think it would be hard to make the most of the money and have a great lifestyle while keeping a low profile and not getting caught.

It costs a lot less than $10M if you want to move to Thailand and live off-grid in some remote area. You can probably do that for a lot less than $100,000, including a Thailand Elite Visa. If that's part of your plan, then just hold onto the money and earn interest, or maybe give it back and hope for a reward. Or just save up the money normally, it's not that much.

I wonder if it's still possible to change your identity in a developed country. Maybe you could move to a new country and start using a fake passport to establish your new identity over time. But I think that stopped being possible sometime in the 90s or early 2000s.

I found it stressful enough just to move to a new country and get a visa legally. I can't imagine also worrying about getting extradited and sent to prison at any moment. Sounds like a terrible life. I wouldn't keep the money.

EDIT: Just reading some of the other replies, and wow, there are some genius criminals in here. Maybe I would take the money!