I have no personal knowledge about VW. But industry standard is using an autosar based RTOS for all real time controller that you mention. Infotainment is most

I have no personal knowledge about VW. But industry standard is using an autosar based RTOS for all real time controller that you mention. Infotainment is mostly android or an OEMs private OS (which mostly means Linux with custom developed apps). Maybe some rare leftovers with QNX or WinCE. A „headunit“ might consist of multiple CPUs, real-time and non real-time ones. I doubt anyone would do a drivetrain controller on Linux or an infotainment system based on a RTOS.