Venom
Go with the one you prefer. Do venom. That was my choice in a similar situation. Yes he might not be as good if they’re bleed immune but he literally shreds anything that does bleed and is a huge help against annoying spiderverse defenders.
Absolutely venom, cull needs like max sig
With that logic Cull Obsidian is severely restricted against armor break immune champs, and both are extremely restricted against buff-punishing nodes, lol. Go with who you have more fun with like others have said, both are extremely powerful where they can be used