Being completely different characters with different origins and powers don't preclude being derivative. Look at Shadow.That's not even an accurate statement though, Spiderman and Venom have aesthetic similarities, but they are completely different characters with completely different origin stories and powers. You could make that argument for Miles Morales, because he's also Spider Man, but Venom isn't. It's like trying to say that Sonic and Crash are the same because they are both furry animal mascots that spin. Or that Minecraft and Terraria are the same games because they are both 2D sanboxes.. or this argument can go on and on.
You claim to be against characters that aren't creative, but your argument isn't very creative in the first place, it's just a pseudointellectual opinion that a million people already have.
Venom is literally Spider-Man's previous suit on a different guy. And yes, that suit is an alien and has powers in excess of normal Spider-Man, and the personalities of Eddie Brock, Peter Parker, and the symbiote are all different, but the character was created to reflect a host for the same suit who lacks Peter Parker's virtues, and the repercussions of such. In a vacuum that's not uninteresting, but even at that point the themes were well worn and tropey.
Venom is the Iron Monger to Spider-Man's Iron Man, and I find that character derivative as well. Bigger, meaner versions who come into being on sloppy seconds of the protagonist. Obviously Miles Morales is more derivative than Venom, and "evil Spider-Man" is reductive, but they're all different strands of that first guy in ways Green Goblin and Doc Ock and Mysterio aren't. Just because he's not a character literally designed to be the opposite like Bizarro and Reverse Flash doesn't mean he's not firmly a spin on Spider-Man.
You can make reflective characters without them being literally a dark version of the character. Batman and Joker are polar opposites ideologically, but you're not going to confuse one for the other. Professor X and Magneto represent opposing methods of leadership in the face of oppression, but one isn't just an iteration of the other.
Venom is inarguably cool, but he's absolutely derivative. That doesn't mean he's completely devoid of uniqueness, not even characters like Scarlet Spider and Miles Morales are, nor is he close to the most egregious case or a "bad" character, but it can't be said he's... y'know... original. I mean Spider-Man literally did it first, and Venom was created to be the insidious version that Peter wouldn't be.
This doesn't really have much to do with Smash though, so if you want to continue we should probably take it to PM.