Transferring my license to a different computer

As a home user I'm allowed to run matlab on two different computers. I just replaced my mac-mini (2014) with a new and more powerful mac-mini (2018) and used the migration assistant to transfer all my files and applications. As I expected, the matlab program wouldn't run on the new mac as I needed to de-authorize the old one, which I did, and I also authorized the new one on the matlab website. Unfortunatly, I still have to download and install everything from scratch, overwriting the existing (up to date) versions of my matlab packages.

What a waste of time, downloading Gigabytes of files that were already on my computer when all I needed was an activation code. Unfortunately, launching matlab invariably results in the error message that forces me to download and install everything from scratch. That's dumb and very furstrating. Perhaps there is a way but I couldn't find it on your website.