What can I actually expense for my small business?

Hi all,
I’m producing a documentary series and that involves quite a few expenses.
A gimbal, a new computer, external SSDs. A second camera operator, a driver, a couple flights, hotels, meals for myself and crew.
But…what actually IS expendable?

I’ll be honest, it’s a bit confusing and I’ve seen really conflicting information online.

To make matters worse, I’m producing this outside of the US.

I would appreciate some guidance