The driver that I installed is exactly that driver that your link points to. If you click on that link, you end up at the page I linked at in my first post: the latest, signed driver provided by FTDI.
I managed to solve it. The BP does not work on the MacBook Pro 2014, but does work on the MacBook Pro 2017. I don't know why, but for me it is good now.
Thank you for your kind answer. I don't have a Windows computer, but tried it on a Linux machine. On that machine, a /dev/ttyUSB0 device appears and I can connect with it using screen.
I still hope that I get the Bus Pirate to work on macOS.
I try to get the Sparkfun Bus Pirate v3.6a to work on a MacBook Pro with macOS 10.14, but I don't get it to work. When I connect the USB cable, no /dev/tty.... or /dev/cu.... device appears. I have installed the latest driver from https://www.ftdichip.com/Drivers/VCP.htm, macOS 10.9 or higher, 2020-08-13, version 2.4.4, but that did not help.