Can anyone use Thor's Stormbreaker?
It
can summon the bifrost and enhance and concentrate
Thor's powers. It is a pretty impressive weapon but it has no enchantment.
Anyone that is strong enough to hold
Stormbreaker can use it. They
do not need to be worthy.
Who can lift Mjolnir and Stormbreaker?
Thor's hammer Mjolnir was defined by the fact that only the 'worthy' could lift it – so basically no-one except the god of thunder (and Vision, for some reason). But when it comes to the weapon's replacement, Stormbreaker – which Thor forges in Avengers: Infinity War –
Groot is able to lift it too.
Is Stormbreaker faster than Mjolnir?
In the MCU,
Stormbreaker is unequivocally “stronger”
than Mjolnir. It was able to effortlessly cut thru Thanos. It deflected a blast from the Infinity Gauntlet. Eitri straight up proclaimed it was and called it a kings weapon.
Why could Thanos lift Thor's axe?
In the final battle against Thanos in Avengers: Endgame, we see Thor almost getting killed by Stormbreaker, and the reason why Thanos can pick it up is
because it was never imbued with Odin's magic. So for all intents and purposes, Stormbreaker is just an axe/hammer.