Mats Valk is dual colour neutral. He solves green and blue as his cross colours. And as far as I see it, CN is a bit hyped. You can be sub 8 with being dual colour neutral. Example: Drew Brads and Mats valk. I have seen some people who are sub 10 solving just red cross. So for now just practice cross + f2l on one side. CN can be done later onwards!
Just my opinion. You can do whatever you want