Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
If you haven't used the HP for a while did you run winupdate before trying anything else? - would imagine, if a few years it would take some time to fully update and many re-boots would be required.
If you log on to the MS Account in your browser does that show this latest purchase? https://office.com/myaccount