Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
1
There is currently a widely reported problem adding and removing devices on the Microsoft account online, this is a server side issue Microsoft need to fix.
Ensure you log into the new device using your Microsoft account, then in the Settings App, enable the 'Location Services' setting for all apps and also enable the 'Find my Device' setting, your device will then get linked to your account online, it may not happen immediately, but it will happen.,
2
I notice you posted your question on the Microsoft 365 forum, are you experiencing any problem installing Office on the new device.