Convert pdf file to mscz file with original words on pdf

Try using Audiveris locally rather than via https:://musescore.com/import

It is possible that the PDF file is too large, even if you use the locally installed Audiveris. This has happened to me before.

Then use a tool that can split PDF pages into smaller blocks, e.g. "PDF Split and Merge" or print it with a PDF printer on a new file, if necessary also in sections, or use the online tool PDF24 for splitting. (https://tools.pdf24.org/en/) and try to split it.

This will create multiple files, but you can copy and paste them back together in MuseScore.

But be prepared to do a lot of rework.