Surfer is high-end 100cl without amping. He's h2h knocked Hulk out without amping.
His reflexes and speed is above lightspeed even without his board. He's done the whole "I punch so fast that it looks like I got a thousand arms and create sonic booms by swinging punching" thing before.
Annnnnnnnnnnnnd, Wolvie won't be able to cut him. Thanos' and Surfer's durability are different. Surfer is nearly as hard as b grade adamantium all the time, Thanos is only invulnerable when he forces his body to be that way.
Surfer one punch k.o's him.