this tool is for exporting Microsoft teams chat data from any user of the organization, with a pst file
The admin who will be connecting to powershell must have the eDiscovery Manager and Compliance administrator permissions assigned
for users hosted onprem keep in mind that if you have never performed a search for a onpremises mailbox you will need to read this article https://docs.microsoft.com/en-us/microsoft-365/compliance/search-cloud-based-mailboxes-for-on-premises-users?view=o365-worldwide
you will need to engage Microsoft support in order whitelist your tenant for a search over a onprem user mailbox.