Stormbreaker is able to focus and enhance Thor's powers. Due to it being composed of Uru, the weapon is nigh-indestructible and able to withstand energy blasts created by the Infinity Stones.
Stormbreaker has the additional power to summon the Bifröst, allowing Thor to teleport anywhere in the Nine Realms. Screen Rant has identified Stormbreaker as the more powerful of the two, based on this ability, as well as it being a much larger and edged weapon.
Still, most of Thor's powers can be performed without Mjolnir. Depending on the iteration, though, Mjolnir can disguise Thor as a mortal. This is something Thor cannot do without Mjolnir. His hammer keeps him safe in and out of disguise, and listens to him as it it were intelligent.
Storm breaker is meant to be the strongest weapon of Asgard and could even summon bifrost, says Eitri. But there is no enchantment or spell on it like it was on Mjolnir. So one doesn't have to be worthy to weild it, just the strength to lift it. Clearly Thanos is capable of lifting it.
Although Stormbreaker and Mjolnir have very similar properties and powers, Stormbreaker is the most powerful weapon wielded by Thor so far. The obvious reasons are that Stormbreaker is the physically larger weapon out of the two, and not to mention that it is an axe, which could well be more dangerous than a hammer.
Why does Thor love Mjolnir more than Stormbreaker?
Mjolnir was his first weapon and he was very attached to it. After all, Thor had the hammer longer than Stormbreaker. Korg: Sounds like you had a pretty special and intimate relationship with this hammer, and you losing it was almost comparable to losing a loved one.
Thor has been shown flying without Mjolnir in the comics but the creators aren't very consistent when it comes to his powers. What's clear, on the other hand, is that Thor can jump and leap very well which can make him look like he's flying.
According to Thor #363, wearing his Belt of Strength doubles Thor's natural power but its use drains him so severely that he would barely be able to walk once he removed it. This weakness has not been mentioned or observed in any other stories.
While no one besides Thor has been able to truly wield the awesome might of Stormbreaker, Groot was the very first being to hold this weapon when one of his arms became the handle for the mighty axe.
If Thor decides to use the power of lightning onboard the Asgardian refugee ship to fight the villain and his minions, he may accidentally damage the ship, or worse, even kill his own people. So, he chose to hold himself back, allowing some Asgardians to escape with Valkyrie (Tessa Thompson) and Korg (Taika Waititi).
Unlike Mjølnir, however, the weapon is not enchanted to prevent those deemed "unworthy" from holding it, making anybody with sufficient strength capable of using the weapon.
But as it turns out, it was not just Thor's strength. After all, no weapon in existence should be able to stop the combined power of the Infinity Stones, no matter how powerful the wielder is. Turns out, Thanos was taken unawares. He had just incapacitated all the heroes who tried to stop him.
I think, quite simply, he underestimated both Stormbreaker and this more godly Thor. He had the power to simply snuff Thor from existence or fire a beam that nothing in the universe could stop. Or anything else he could imagine.
There's been confusion among fans about whether or not Loki is worthy of wielding Thor's hammer, but Marvel has finally confirmed that the God of Mischief can indeed lift Mjolnir. The Immortal Thor #4 complicated the issue of Loki's worthiness by not allowing him to solely be the one to lift Mjolnir.
In a moment of wistful affection for his girlfriend, Thor asked his trusty hammer to always protect Jane, and in doing so unwittingly enchanted Mjolnir to do just that. Just like Thor's father Odin once enchanted the hammer to only be lifted by someone who is worthy, Thor cast a spell that let Jane use its powers.
Although Kratos never gets to wield the hammer, given his own extraordinary godly strength that slightly surpassed even that of Thor and even being able to hold Mjolnir back with his bare hands when Thor threw it at him, it's very likely that Kratos would be fully capable of using the hammer if he wanted to.
On their own, both these noble heroes are capable of beating incredible forces. But for all Shazam's power, he does not match Thor's experience in using the more arcane elements of his abilities.
By most accounts, Superman seemingly outclasses Thor in terms of raw strength, especially in earlier versions of the DC Universe. He's pulled planets, punched people into orbit, and performed all sorts of wild feats of strength.
Only Thor can produce lightning without Mjolnir. But the point of carrying Mjolnir means whoever carried it are worthy to be the king of Asgard and gets the power of the God of Thunder. But if someone wields the hammer and if Thor is still worthy of wielding the hammer, than the 'someone' couldnt produce lightning.
In the MCU, Stormbreaker was forged by Eitri at the behest of Thor, as a weapon to use against Thanos and his Infinity Gauntlet. In the comics, however, Stormbreaker was still made by Eitri, but pretty much everything else is different.
During a Vudu Viewing Party for Avengers: Infinity War, co-directors Anthony and Joe Russo revealed a key difference between Thor's hammer Mjolnir and his new ax Stormbreaker: the latter doesn't require worthiness. That's why Groot was able to lift the ax, not because he was worthy but because he didn't need to be.
Can Infinity War Thor with Stormbreaker beat Endgame Thanos without the Infinity Gauntlet? No he cannot. However L&T Prime Thor with or without Stormbreaker would curbstomp Thanos. He's far too strong for Thanos in his L&T Prime.
