Acceptable to cut steak before searing? I have a rather dumb issue; I have some cuts of steak that are too large for my cast iron, and if I tried to cook them, the ends would be lifted into the air which I assume is not preferable (although I am no expert). Is it fine to cut the steak when it is raw or will it do something terrible to it?

I am of the mindset that it is just cutting the raw beef, so no juices or anything will run out like cutting a steak before letting it rest, but again, I'm no expert!
Why would it not be acceptable to cut raw meat? It was already cut from another larger piece of meat that was cut from a whole animal. Nothing terrible will happen. A steak is not a bag of juices, nothing significant will leak off of it.

It's indeed better to cut in a smaller piece that fits your pan, the whole steak should touch the bottom of the pan otherwise you might have uneven cooking  / raw ends.