Rank up question 6*R2 or 5*R5?

Gnotnus

I'm at the point to decide to rank up one of my 6* or 5* champs to rank up. Please share your thoughts which will be better options. I now have only one R5 5* which is Corvus, and didn't finish variant except the moon quest.

Gnotnus

I accidentally click enter so I couldn't list rest of them but I also have other champs on my list to consider to rank up..
5* Sunspot
5* Blade
5* Hyperion (Duped)
6* Luke cage (Duped)