Erick apparently trolls:

[does the crop factor change resolution]

Take a resolution chart and cut it in half. What do you think: have
you changed the resolution?

What will be the best buy for widelife photography: EOS5D with Canon 400mm
or NIKON 200D with Nikon 400mm
10 megapixel + 1.5x or 12 megapixel FF

Your questions, if honest, suggest you wouldn't be able to tell the
difference at this point, even if the answer was available (few people
have more than one set of high-end gear, and really, at this level, one
is almost picking at nits resolution). So why not flip a coin?
It's gonna be many kilobucks either way.