It may depend on how old the files are. Older iTunes files were Digital Rights Managed protected and cannot be used in any editing program while newer files mainly in the AAC format are not.
However, as far as I'm aware Magix Movie Studio does not support AAC sound file import. Video Pro X however does.
I also tried my old Vegas version of Movie Studio 16 and that would not import AAC files either but that was a different program to the new Magix version.
Vegas MS 16
Movie Studio 2022 ( Movie Edit Pro, same program, different name)
Sorry, I should have added that while the aac format is supported within another container format for use within a video file, within MMS and previous versions of VMS, the AAC sound file format on its own is not
Weirdly, for a short while it was supported in Movie Edit Pro 2018 and possibly before that (I started video editing in 2018 and used aac sound only from my camcorder which supplies a separate aac sound track when filming in slow motion). For whatever reason though now aac sound files on their own are only supported in the more advanced editing versions of these programs. Video Pro X for Magix and Vegas Edit and upwards in the Vegas product lineup.