There's your problem, right there. "Lean" is execu-speak for "Not hiring enough people to do the job."
"Startup-like" means, "We got funding but we're still not willing to hire enough people."
In "lean" organizations, everyone is wearing a lot of hats, many in areas they really don't know much about, so they desperately try to get tasks off their plate, even if it means doing a mediocre job.
With a constant shortage of personnel, things deteriorate anytime someone is on holiday or out sick, so the pressure never to do either is immense.
And when there's an actual emergency, there aren't enough people to handle it, so everyone drops what they are doing to run around like a chicken with its head cut off.
I'm sure you never noticed it, but it's impossible to tell anything about what sort of business you are in! Your whole screed is management-speak, without any actual interest in your actual business.
I don't expect your "lean operation" to last very long, but I am absolutely certain that it will continue to bring agita, stress and misery to almost all its employees as long as it does.