i mean without moral bias and looking at it with a black and white perspective, it honestly only comes down to two consenting adults (unless there isnt consent but that's a whole different issue)
adding morality to the equation, it's one of those things that are just inherently and utterly disgusting and we dont even know why. like we know it's because it's literally family, but why?
like one day in our societal development we were just like "ew no lets not do this anymore" when before, marrying cousins was pretty normal. though that statement's obviously not taking into account the actual disgust that people may have felt towards it, since it was a while ago. that and society probably found out the dangers and problems that incest causes.
and if you add in biology, incest is definitely NOT okay whatsoever especially for reproduction purposes
at the end of the day, it's not really my business. not gonna defend it or condemn it especially if it's consensual and not an abusive kind of thing. i guess my stance is do what you want but make sure no harm comes from it and be ready to potentially face serious consequences for your actions