I hear ya! I have worked in many groups in which there was a person (or 2) who did not have the ethos of shared values or even the capacity to work as a part of a team. This can only be dealt with bya finite number of options. Maybe the person is taken aside and asked why they wish to be a part of the team. At this point, when people explain their position they actually realise their position and convince themselves more effectively than I ever could. There is magic in hearing your own thoughts out loud.
Compromise is employed at the behest of the collective upon realising there is some logic in the ideas of the dissenters.
The person is told in no uncertain terms that they add no real value to the team vision, at this point I would thank them but explain that there is a mindset involved in a spirit of cooperation.
I would be incredibly hesitant about taking on a huge project myself again after burning out or coming close to it many times over the past 3o+ years of work and project involvement.
Thankyou so much for stopping by to share your thoughts, much appreciated. Have an awesome week :D