everything Flash can do, Surfer can do too and more so.
in DC you have the Speedforce to enable Flash to travel at >C speeds without taking on infinite mass, in Marvel you have the Power Cosmic and/or Hyperspace to do the same thing.
if Flash can "IMP" people then, naturally, so can The Surfer. all that an IMP entails is a loose application of "real world physics" at C-speeds.
Surfer could just spit at Superman, whilst travelling at 1000x C and ka-boom ... Superman's thrown to the other side of the universe 😄.
Surfer's faster than (or at the very least as fast as) Flash, and given his uber powers he'd tag and destroy Flash in 10000ths of a second, because both can move and operate at those speeds. it would be an epic chase but, for observers it would hardly last long enough to blink.
Surfer could also empower Thor to Surfer levels by boosting the Odinforce and adding Power Cosmic attributes (10000xC speed, uber durability, Cosmic Awareness etc), making Thor ridiculously powerful and dangerous.
Thanos ... well he could wipe out 2/3rds of the JLA with a blast, then just teleport and capture Superman, break his neck, then take out Wonderwoman ... it's just easy for him.