Blue
Ravenous Bugblatter Beast of Traal
Captain America used lightning in Avengers: Endgame, so we know that Mjolnir has mojo of it's own. Which makes sense, we know that Stormbreaker has mojo of it's own. Mjolnir might even have more, since the All-Father trapped Thor's power in it in the first Thor movie.I also disliked that, after Infinity War and Endgame stomped all over the "your hammer wasn't the source of your power, it just channelled it, you no longer need it" character development, this movie just doubled down on that, having Mjolnir granting full-on Thor powers to Jane.
This is something that was already made canon in a previous movie, just with the dial turned up a bit. Potentially explained by Thor's love, connection, and debt to Jane. Or explained by Jane already having been the vessel for power in Thor: A Dark World and able to accept more of it, especially in her time of need due to the cancer.