Despite being broken, Thor: Love and Thunder saw Mjolnir be fixed, with Jane Foster wielding the hammer, and there is an important reason why that was possible. Mjolnir is one of the most powerful weapons in the Marvel Cinematic Universe, which is why Cate Blanchett's Hela breaking Thor's hammer without much hardship in the best of Marvel's Thor movies, Thor: Ragnarok, was a shocking moment. While it seemed like Mjolnir's time at the MCU was at an end after Thor forged Stormbreaker in Avengers: Infinity War, the magical hammer came back in full force for Thor: Love and Thunder.

https://screenrant.com/thor-4-love-thunder-mjolnir-fixed-jane-foster-mighty/