Yeah it's a MU I struggle heavily with on both my mains.. haven't played it as Swampy yet.
i haven't had a lot of success, but when I am doing decently well it's because I'm really watching his venom use and trying to make solid reads against his options.
When I play wussified against him, I get eaten up, but when I make a read on what he's doing and just commit to punishing him I seem yo do better. Yeah, sometimes that's the wrong read and you get shit on..
Don't let him corner you, and push block him when you think it's safe. Remember clash puts him in debuff. Find out what you have that's grab immune for starters. Knowing that and using it can really start to make things manageable.
Bane is a huge issue for me, it feels like I can't do anything at all, which obviously isn't true, but he can be overwhelming vs some characters. I think he requires just solid game awareness and such. Watch his trait, use your MB rolls and push blocks to stop him before he gets momentum. Vary your wakeups. Don't make it easy on him.
Also, fuck his unclashable 9000000 damage corner combo.