Sohail_Tariq I appreciate the details in the response, and I thank you!
My only issue with this is that if the OEM's image is older, or out-of-date by a major fix (as we have seen in the past), I'd like to try to get the customer updated as quickly as possible. Generally the biggest issue is a sign-in error, which makes it impossible to manage in the Teams Admin center or anywhere else other than with Intune, which a lot of customers are not necessarily domain joining the MTRs.
In most cases this isn't too big of a hurdle, generally the update happens within 24 to 72 hours and this is exactly what we expect. But when it doesn't, and the customer is trying to use the system, forcing the update is a lot of the time the only way we can get passed the error and get the system functional.
Using this method for testing and our own purposes is typically what we do. But I think a good way to update the MTR system manually (preferably with a flash drive) WITHOUT the OEM having an up-to-date image, would be a welcome addition to anyone performing troubleshooting and support.