I don’t think you need “sort of” for gender fluid. When you’re an omnipotent being of pure thought, you’re whatever gender you wish to express yourself as and you almost certainly express it as different genders for different situations on different planets and societies if you’re like Q and you want to spend eternity fucking with them.

I’d also say Odo was gender fluid. Or at least he’s a literal fluid with no gender unless he wishes to have one. He’s not expressing a gender when he’s in his bucket.