The trackpad on the latest Magic Keyboards for the new iPad Pro M4 (11-inch and 13-inch) is currently not compatible with the Citrix Workspace app on iOS.

Current Solution

If you're using a version prior to 24.6.0, we recommend using an external mouse (either wired USB-C or Bluetooth) to navigate the screen.
If you're using version 24.6.0, you can use the trackpad provided the Pointer button tool is disabled when inside the session.

Please Note: With the upcoming Apple release of iPadOS version 17.6, along with Citrix Workspace App 24.6.0 and later, the trackpad is expected to work seamlessly on iPad Pro (M4) devices.