Package manager not compliant with eOS documentation?

Hello
I prepare my S9 tu upgrade to
/e/OS 4.0
So i search a reliable mean to backup apps ; i found this tuto https://doc.e.foundation/support-topics/backup-and-restore-ephone.html which seems to be helpfull , and install Package manager
BUT when i get the apps list , impossible to tick the boxes to select apps to backup

I install the free version of Package manager , is that the cause of this failure ?
Or the failure is caused by “the interface between the seat and the phone” ? :face_with_bags_under_eyes: