Family Tree Maker genealogy software certainly supports export to PDF format, but it's done from the main .ftm or .ftw file and not from the .ftmb backup, which means direct ftmb to pdf conversion is not possible this way.
If you want to export content from the backup, you have to first restore it using FTM. If you have issues with recovery of FTMB backup files, it might be actually best to reach out to the software's support or online community for help.
Updated: October 30, 2023