Fincher probably wouldn’t mesh well in the MCU then, considering he’d have to follow a pre-established plan for his film and highlight a previously established hero.
He may surprise us one day by signing onto something, but I wouldn’t hold my breath.
Some have speculated David Fincher’s aversion to outfits like DC and Marvel comes from his experience on Aliens 3, which he has since disowned as a film due to studio interference and other things of that nature.