SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world. And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download (registration required) various documents highlighting:

System Workbench for STM32

cannot open project from project tab in version 6


Which version of which tool?
System Workbench for STM32 is in version 1.4.0 (1.5.0 is due next week) while CubeMX is in version 4.10, so I really don’t understand what is your problem...
Anyway, in System Workbench, if you want to open an existing project file, you can’t just open it as a file, you must import it in your workspace, using the “Import...” menu item, either from the project explorer contextual menu or from the File menu.