Then the problem is it would take a couple of days to go through all the waiting tabs and shut them down, and you don't have a couple of days to spare.
Eventually you just save them all out as a session and start again, and hope you will learn from your mistakes ;-)
I've switched from FF/Chrome to FF/Vivaldi because it has much better ways to handle tabs and bookmarks than Chrome does. Vivaldi does tab stacking, for example.