This can be done due to many reasons, especially because the Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x00000000000000f8 can be somewhat vague.
If you start the engine and get an immediate crash, you most likely have installed the plugin incorrectly or miss dependencies which may be required.
Make sure that Quixel Megascans plugin that is compatible with your version of Unreal Engine, and check if there are any conflicting plugins or third-party software that may be causing the crash.
Deleting the Saved and Intermediate folders in your project directory, then re-open the project and try applying the Quixel Megascans plugin again may also resolve the issue for you.
Finally: Make sure that your system meets the minimum requirements for running Unreal Engine and Quixel Megascans. Check the system requirements in the Unreal Engine and Quixel Megascans documentation to ensure that your hardware and software configuration is compatible.