For MacOS, install "The Unarchiver:
https://theunarchiver.com
Then right click on the last part of the archive file (e.g. in this case, the second file of the download from wetransfer) and choose “Open With” and then choose “The Unarchiver”
Depending on the folder the RAR files are in, it might warn you that it doesn’t have access to the folder. Just click on the “SEARCH” button at the bottom right, and it should then work.
It might ask you for the folder to extract them to.
I have just tried this now on my old 2009 macbook, running El Capitan and The Unarchiver V3, and it works perfectly.