Anthony Joshua would have a pretty good chance. Wilder don't have the cheen to firefight with Golovkin though
Eubank Jr (being genuinely serious). Only question is whether he could make the weight. No one under 175 is stopping Eubank and with Golovkin older and prone to shipping punishment, Eubank takes him apart. Eubank is far, far bigger and his work rate is too high.
I just have to ask - are you for real? There’s a reason he lost to Saunders, there’s a reason he was clowned by Saint George and that exact reason is why he lost his pen when the time came to sign for the fight with Golovkin and Brooks got taken apart instead. Work rate means dick when you’re backed up and trying to survive.
A jab from a 6’1” Groves is a lot different to a jab from a 5’10” Golovkin who loves to brawl. Golovkin v Eubank is a Mexican brawl everyday and at this stage, Eubank has too much for old man Gennady.
You have to either be extremely tough and willing to trade, or extremely slick and able to box. Only person that fits the latter at Middleweight is Billy Joe.
He wouldn’t go the distance with his “i’ll just jump in with a punch and hope it lands because I have no idea how to close the distance without getting a jab in my face” would see him KTFO sooner rather than later against someone like Golovkin, who’d consider such tactics as a gift from God. So yes, he would backpedal and yes he would do so to survive and counter where (if able to) possible.
Canelo, Jacobs, Charlo, and BJS all have the ability to get a win over GGG, but none of them are willing to take the risk necessary to pull it off. Single shots don't seem to do much damage to GGG. Well placed combos are what get GGG's attention. Jacobs stopped GGG in his tracks every time he stood his ground and put his weight into a 3-4 punch combination. However, every time he stopped GGG instead of pushing forward he would backoff and voluntarily go back on the defensive. I still think that Jacobs was so delusional to think that he won. Every time he voluntarily backed off and didn't capitalize on GGG he was giving rounds away. Canelo was having success to GGG's body, which isn't as durable as his chin. However, GGG adapted and started firing his jab and kept it going the whole fight. Canelo wasn't willing to take any risk to neutralize GGG's jab and going back to the body. He was content with staying on the backfoot and barely taking a step forward the rest of the fight and got a gift draw. Charlo has the power and ability to be a threat to GGG, but he also has a bad habit of relying on single punches rather than combos. Also, his defense is very needs work. BJS has the handspeed, footwork, and timing to make GGG look bad. I wouldn't mind seeing if he could neutralize GGG's jab.