All Open Foris tools (being web or Java based) work in Mac computers!
Ok, a bit weird you may think as this is the kind of dialog that you see when you try to run the installer :

Sadly we haven't had so much time to fix this installation issue, this means that in order to install Collect/Calc/Collect Earth you need to "unlock" the installers. This is fairly easy to do. Instead of double-clicking on the installer when you download it, you should click on it with your shitf-key pressed. That opens a contextual dialog, then you choose the first option, "Open"

Now the dialog that comes out you see has an "Open" button that you can click on to start the installation :

This is a link on the MacOS support system about how to do this process in some other ways : https://support.apple.com/guide/mac-help/MH40616/10.14/mac/10.14.3