In Thor #21, the being inside of Mjolnir lashed out at Thor, and the reason makes it seem like Thor's angry ex. This changes everything about Marvel's history, and it could also impact the MCU.
The short answer is yes, Thor is still worthy of lifting Mjolnir after Thor: Love and Thunder. His worthiness comes down to the reason why Mjolnir chose Jane. In the comic books, Mjolnir does choose Jane to be Thor after Thor becomes unworthy and is unable to lift it.
However, despite creating his own lightning sword to take on the God of Hammers, Thor is brutally injured when trying to punch her, as Mjolnir blocks the blow and shatters the God of Thunder's hand in the process. Thor is stunned after learning Mjolnir has broken him, as his former weapon hurt him like never before.
Mjolnir is a connection to Thor as he is pre-Infinity War, still finding his footing as a hero and learning how to find power within his relationships instead of within his physical ability. In this sense, Mjolnir is almost like a best friend to Thor.
During the events of Thor: Ragnarok, Hela (Cate Blanchett) shatters Mjölnir into dozens of small pieces. In Love and Thunder, we learn that all the pieces of Mjölnir are kept in New Asgard, as a touristic attraction to those who wish to see the God of Thunder weapon.
The chemotherapy is attacking the cancerous cells but Mjolnir doesn't identify the cancer as an illness just as another part of her it needs to protect. Plus chemotherapy really does weaken Jane and make her sick so it's easy to see as an illness on it's own.
Hence, Mjolnir determines worthiness based on Odin's definition of worthiness. However, since Mjolnir also has a conscious being within it, in the form of God Tempest, another likely explanation is that it is God Tempest that determines the worthiness.
Both weapons also appear to have a degree of sentience, with Stormbreaker apparently being envious of Thor's affection for Mjolnir, a characteristic director Taika Waititi attributed to the handle being made from the arm of the adolescent Groot, and carrying over some of that character's moodiness at that age.
Thor had numerous love interests in the comics, and often he was involved with more than one woman. However, his most notable love interest, and best known to fans, is Jane Foster. Jane had become God of Thunder in her own right. Most recently, Thor was involved with She-Hulk.
Like Stormbreaker, Mjolnir also allows Thor to wield thunder and lightning; however, it's not capable of summoning the Bifrost. The magic hammer did develop a power Stormbreaker couldn't, though, and it's able to detach its broken pieces to attack multiple enemies at once, before coming together again.
There are very few powers that Mjolnir grants him, but it does seem to amplify his connection to the Odinforce at all times, and accordingly, powers him up. Still, most of Thor's powers can be performed without Mjolnir.
Can Thor fly without Mjolnir? Yes, he can, and he did in Thor: Ragnarok. Thor's powers do not come from his hammer, but from his own body.
Thor has been defined by his weapon and whether or not he can lift it. While losing Mjolnir undoubtedly makes Thor a weaker fighter, but a much stronger character; now, the question of worthiness is up to him, and he cannot rely on a weapon to tell him if he's doing the right thing.
Other Marvel characters have lifted Mjolnir not through worthiness but through technicalities such as absorbing Thor's powers, including the Air-Walker, Awesome Android, Magneto, Rogue, Wonder Man, and Doctor Doom.
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.
However, the film also implies that the hammer only sees Jane as worthy because Thor unintentionally revised the rules of Mjölnir, giving it the power to protect her. Captain America didn't need anything special for the hammer to see him as worthy – he's able to wield it without issue in Avengers: Endgame.
He's lost his Mother, his girlfriend Jane, his father Odin, his brother Loki (three times), Mjolnir, his eye, Asgard, and his friends in the fight with Thanos. While thoughts race through his mind: he finds himself asking: What's the point of loving [someone] if they're just going to be taken away?
Thor Odinson initially suspects Jane might be this new hero. But he eliminates her from his list of suspects because she is going through chemotherapy for breast cancer, which, he reasons, would make her too weak to fight.
Jane Foster is a superhero appearing in American comic books published by Marvel Comics. The character was introduced as a love interest of the superhero Thor Odinson until becoming a superhero in her own right.
The Asgardian Son of Odin was extremely close to ending Thanos at the end of Avengers: Infinity War. After gaining the powerful weapon Stormbreaker, Thor becomes the wielder of the most powerful weapon in the universe. Stormbreaker is capable of killing Thanos outright, and only Thor is currently worthy of wielding it.
The hammer Stormbreaker is very similar to Mjolnir, made of mystic Uru metal and is nearly indestructible. Worthiness: Just like the original Mjolnir, no one can lift Stormbreaker who is not worthy.
Valkyrie gets run through with the Necrosword, resulting in her losing a kidney, Thor loses Stormbreaker which will allow Gorr to reach Eternity, Jane learns that she will die if she uses Mjölnir again, and they are unable to rescue the children from Gorr.
Yes, even Spider-Man has been worthy of holding the hammer of Thor.
And Mathaudhu can cite documentary sources to back him up. For example, Marvel – which publishes the Thor comics – issued a “Thor's Hammer” trading card in 1991 that states Mjolnir is made of Uru and weighs precisely 42.3 pounds. That's lighter than a herd of 300 billion mice, much less a herd of 300 billion elephants.
While Captain America and Captain Marvel have briefly lifted the weapon in different situations, the friendly neighborhood Spider-Man is yet to do so. Interestingly, this puts him in line with the other superheroes, such as Iron Man and the Hulk, who can't lift Thor's legendary hammer.