MS has stated that the license is digitally linked to my MS account on my HDD
The license is not linked to the account. The license is assigned to the computer, and this computer (the licensed device) is already linked to the account (when the owner of the PC changes, the license remains on the PC itself). This was called a "digital license linked to an account." The name is not very correct and misleads many users. In this case, the PC vendor most likely activated the OS in one of the illegal ways when installing the OS. When changing the HDD and installing the OS cleanly, the activation services determined that there was no license and "refused activation." Changing the hard disk itself is not a "hardware replacement" and activation remains if licensed. For verification, you should contact a Microsoft support agent in the chat. He will have the opportunity to remotely connect to your PC and check everything on the spot. To do this, log in to your personal Microsoft account on the page https://support.microsoft.com/en-US/home/contact?SourceApp=smc2&ContactUsExperienceEntryPointAssetId=www.microsoft.com
In the search bar, type (without quotes) "agent support" and press Enter or click on Get Help. Ignore the search results, and click on the "Contact Support" button at the bottom. On the next page, select "Windows" and "Technical Support" from the drop-down lists, and then click on "Confirm". Next, select the chat "Chat with a support agent in your web browser" and on the next page, enter (if requested) your email address and click on "Confirm". A chat window will open in a new tab. Wait for the response from the support specialist and describe the situation to him (to speed up the process, you can provide him with a link to this discussion). You may also need documentary proof of the purchase of the license (photo or scan of the receipt from the store, etc.). After checking the license (if it is valid) activation will be restored.