Does a PhD student and first author choose the journal or their supervisor?
This is in the case where negotiations have failed. Who should get the final say or keeps this right?
All authors have to agree to the publication of a paper, and any author can veto signing away the copyright. So, keep negotiating :)
Things you should consider:
All these points count against you. You have the right, of course, to fight for the paper to be submitted to the journal of your preference but you should consider whether this is really a battle worth fighting. In my opinion, it is likely you will be better served by choosing a different hill to die on.