In case people still struggle with this, using a Mac the commands for the Cursor IDE are as follows:

• Collapse all: CMD + R + 0 (zero)

• Expand all: CMD + R + J

To collapse/expand only a class or method, click with your cursor on the class/method's name and then use these commands:

• Collapse class/method etc.: CMD + R + [

• Expand class/method etc.: CMD + R + ]