"I've chosen to be what I am. (as a profession)"
This doesn't sound like you're talking about a profession necessarily. It sounds more like something you'd say during an argument about something you do that might be considered odd by the person you're arguing with. Let's say, for example, that you like to dress up in animal costumes and get together with others who do the same. You might get into an argument with someone who cares about you who thinks it's odd behavior and you would say this during that argument.
"I've chosen to be what I want to. (as a profession)"
It took me a few minutes to figure out why this sounded so unnatural to me. It's because you're missing a word.
"I've chosen to be what I want to be."
You need that extra "be" at the end. Otherwise something just feels off about it. Also, with or without "be," with no context, it sounds much like what I said above. It sounds like something you would say during that type of argument.
As a small note: Your first four sentences sound like song lyrics. I don't know if you meant to write them that way.