Stormbreaker Thor and Post-JL Superman easily. Firstly, the two of them can easily put him down. Stormbreaker cut right through the IG's beam and into Thanos, showing that it basically has the power to override the IG(Raw power only obv), however we clearly saw in the recent Infinity Wars event that the comic IG(which while weld by Gamora isn't really any better then MCU) could easily manipulate Thor and those more powerful then him, so it isn't a big deal. Secondly, Superman is far, far faster then him. Flash was stated to be lightspeed in an extra info thing, and since that's the director's word, it should apply as law(Feats are just the director expressing word on screen), which would make DCEU Superman LS at least in combat and really good at statuing people. Therefore, Thor doesn't even have a chance, he's fighting someone that he will be not moving against and someone who can one-shot him casually, hell Superman can take Stormbreaker and chop off his head.