In a GNU / Linux environment there would be no big problems, we just need to install zstd. With Windows it is necessary to "tinker" a little more, starting to install the free PeaZip software ( here to download it) one of the few that allows us to decompress files in this format.
We will then have to unpack the backup file, go to the folder and unpack the various .tzst archives. We remind you that in Plesk backups the data files that make up our PrestaShop or Wordpress installation are located in backup_user-data_xxx .tzst , while the database data is in the "databases" folder
We then position ourselves with the mouse on the file we want to unpack and click with the right button.