Need cosmic rank 5 advice

ClassicStorkYT

I have a cosmic 4-5 gem but am torn on who to rank up and use it on. I already have herc and hulking at r5. I have opened two cosmic abyss nexus crystals in hopes for either Cgr, Ronan, or king groot. At this point, I give up on the nexus’s and will probably go science when the necropolis death rewards come out. Who should I take up? (I’m not picking knull)