His comment there wasn't about KO, it was about how there's a fucking hero in the dinner party.
And again, the idea of him showing up "after Venomous saw KO" is certainly a point of interest, but then there's tons of other shit that points in the other direction, like how the two of them act completely differently.
Venomous even said that POINT is constantly on his back over shit. If that was the case, they'd find out about him being SF pretty easily.
And why would they have SO much shit pointing to them being the same guy, but then their body types are noticably different, the way they act is completely different, and most importantly their levels are different? I somehow doubt his coat adds -1 to his pow card just cause.
Also, there's just no narrative meaning or weight to SF being Venomous at this point. They have the similarities you've pointed out, to the point where it's almost blatent, but what does it really mean if they're the same guy? We just shift SF's importance to Venomous.
If they're not the same guy, but rather related, we get way more interesting plot threads, both leading to the reveal and afterwards.