Which cosmic should I upgrade?

I have 4 cosmic champions now, all 4*.
I'm confused in what to upgrade?

Comments

By the way, none of them are duplicated

Cull is getting nerfed, so I would wait for him.
King Groot is garbage.
Drax is ok, but Venom is a beast, and he dosnt need awakened.

Cull is great, but he's a bit squishy, so I would go with Venom myself

By the way, none of them are duplicated

Venom is still good as an unduped.

Wait and see what happens to Cull

Thanks to all. I'll keep venom and cull on hold then. I had upgraded Drax in the past, and so I'll save iso for later.