In a sense, I think you’re both right.
There’s no reason Venom (and potentially that Joker movie) couldn’t be great. Logan is a tricky comparison, because it has the obvious star power of Jackman and Stewart and at least some continuity with the rest of the franchise, but Logan could’ve had all those elements and still been a failure. But it had the freedom to take some chances, and to tell its own story that wasn’t tangled up with a franchise, even if it was born of one. Talent in front of and behind the camera and a good script could probably make a great movie from just about any comic character out there—even a character that has a symbiotic relationship with another (figuratively with the Joker/Batman dynamic, literally with Venom/Spidey).
But I also don’t think you have to be the most jaded cynic in the world to look at the plans Sony keeps floating for their Spider-Man Movies Without Spider-Man and see that they’re grasping at anything they hope they can hang a franchise on and will probably just churning out bland studio-contract driven results unless they stumble into a good movie by accident.