I have a laptop from 2012 and a desktop PC from 2020 with the "latest" hardware available.
When I go to "Check for updates" on the laptop, it takes 10-15 minutes to get a result (even if this means that there are no updates).
With a desktop PC, it doesn't take a minute. Why is that?
These differences also occur if the laptop is connected to the router via a patch cable and the desktop PC is "only" in the WLAN.
That will probably be due to the search order of the drivers. Most likely in 2020 are drivers from 2020, then you have to go back again and again.
So the newest box is the quickest to clear, the oldest takes the longest.
Unfortunately, you did not guess the system used. However, one reason could be a slow hard drive. Take a look at the load in the Task Manager while it is calling for updates.
