I would also leave out "despite my best efforts". That makes OP sounds like they have a hero complex, as if they could have single-handedly saved the startup somehow. If the founders are driving it into the ground there's nothing the employees can do, and it's best not to come across as deluded about that.
Meh, I could see it both ways. There’s a difference between “I saw it sinking and figured I’d ride it out collecting a paycheck” and “I tried my butt off to do whatever I could to save it, along with everyone else, but the effort just didn’t work.”
