Hi Paulo,
generally speaking an Embedded Wizard driven GUI is totally independent of the used (RT)OS. A GUI can also be executed on bare metal without any (RT)OS. Or with other words: You can use any operating system - hence also Zephyr. Moreover the integration of an Embedded Wizard driven GUI belongs to our customers as the GUI is only one part (and not the dominating part). When it comes to the MCUs we always use as a base what is provided by the semiconductor manufacturer. And this is - as of now - often FreeRTOS - but not Zephyr.
When using our Build Environment as a base, the most important files to be adapted are ew_bsp_os.c/h as found within the folder /TargetSpecific. As this is provided as a reference and example implementation, customers adapt that according to their needs. There are no other locations that have to be adapted.
However, it is worth mentioning, that integrating Zephyr as a complete system abstraction (as it is the case for Linux) may come with certain challenges. From our experience, the main Zephyr project often lacks direct support for hardware-specific, graphics-related components, such as display controllers or graphics accelerators. This lack of out-of-the-box support frequently requires developers to manually integrate key functionalities which are already provided by the main Software Development Kit (SDK). And unfortunately, this additional work can lead to a software architecture that we consider somehow sub-optimal, as it introduces complexity and can hinder the clarity and maintainability of the system.
I hope this helps.
Best regards,
Manfred.