Venom has helmed his own own series as a protagonist and/or a hero from time to time. Sometimes it is okay. Sometimes it is not. But he doesn’t have a memorable stable of villains. Largely he has fought Marvel C-listers when he’s being a hero, which is usually not a good sign.
Carnage could conceivably be a villain for him if they follow the model of totally rewriting the character they’ve done with Venom.
I don’t really see that as a positive, though. Venom’s own series were among the slighter (and most 90s) of the 90s comics, and attempts to revive that in recent years (Venomverse, Venom Inc, Poison X, Venomized) haven’t exactly been either a commercial or creative success. And Carnage is even worse.