Should I rank up my 4* task master?

NIOBBB

(I already have a 4* gwenpool @R4/40 , 4* Black Bolt @R3/30, 4* War Machine @R3/30, 4* venompool @R3/30, 4* Vulture @R3/30)
(I also have 4* cyclops @R1/10, and 4* @R1 winter soldier)
(And which one should I rank up to R4? Gwenpool is already on R4)