Windows delivery optimization doesn't work?

As I primarily use Linux, my windows machines mostly lie on the shelf. It may be months between the times I use any of them.

When I take it out and switch it on, it will typically block my internet for like half a day or more (on my slow internet).

Then when I start the next windows computer it doesn't download it from my from the first computer, but downloads it equally slow from the internet.

Update: The solution:

The downloaded packages are cached for a limited time (by default 3 days I think). So if you have several computers that you want to update, the you should start them up within this time, after the first computer has updated.

https://www.tenforums.com/tutorials/105396-change-delivery-optimization-max-cache-age-updates-windows-10-a.html

To find how much is in the Delivery optimization cache

Google "Clear the Delivery Optimization cache" found this: https://support.microsoft.com/en-us/windows/clear-the-delivery-optimization-cache-c0e93802-5800-5554-7380-594014a6089b