Hi CANNELLE,
Unfortunately this is not possible from either PLN / PLA files or from BIMProject / Archive files. Current participants of a project is stored within the BIMcloud Server's databases, and none of our applications registers how many hours a user worked with them. If you already uninstalled all of these applications, I'm afraid there's no way to gain these informations.
Kind regards,
Noémi Balogh
Customer Engagement Expert, Community Admin