If you have a few characters that could deal big damage/clear lanes then it wouldn’t be the worst idea to go with venom. He’s great for variant 2/5 and he should be good for the upcoming villain variant. Beating the Variants will be a huge help with your progression because of those sweet 4-5 rank up gems. It also doesn’t hurt that he’s one of the best champs for incursions.

CMM is a better overall character but she has a few drawbacks. She needs to be awakened for a lot her utility and she’s unfortunately dependent on the Nick Fury synergy to keep her charges up. However, I do have to mention that Corvus becomes less useful in the last couple of chapter of act 6. The health pools become so large in 6.3 and 6.4 that he can’t just quickly nuke down opponents. CMM would probably be a better lane clearer for those chapters. Your decision should probably come down to what content you want to beat at the moment.