Blockquote
Is there any other source to get the flash program?
Yes there is. I will try to update a MacOS setup for the Zigbee2Mqtt repo that works off the linux setup mentioned here: GitHub - Frans-Willem/AqaraHub: AqaraHub is an open-source Zigbee hub for Xiaomi Aqara devices. It aims to be a replacement to the Xiaomi Gateway that does not require communication to outside servers, and uses a saner communication option (e.g. MQTT).
The repo for the flash tool I used is GitHub - dashesy/cc-tool: Mirror of cc-tool from SourceForge that was also mentioned earlier by @airdrummingfool
For MacOS I was able to install the mentioned dependencies: libusb, boost, pkgconfig using homebrew. Example:
brew install libusb