Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Does the Office installation appear to complete, even if it is slow?
Are you saying that you see the error when you start an Office app? Does it happen with all the apps or just with some of them?
One thing you could try is an Office repair. An Online Repair is more thorough, but note that it usually forces a reinstall of Office. See https://support.microsoft.com/en-us/office/lifecycle/repair-an-office-application .