Hi,
I'm Sumit, here to help with your query on the Microsoft Q&A forums.
Apologies for any inconvenience you are experiencing. I am happy to help you today.\
The Serial number feature is exclusive to Surface devices, so it will not work.
The device list at https://account.microsoft.com has been experiencing an ongoing issue for two weeks, where the device list does not update sometimes with new computers. I recommend waiting for 3 to 4 days, and the PC should sync automatically. Just ensure your Microsoft account Storage has some space at least.
I look forward to your response and am eager to collaborate until we find a solution.