TIL I learned that I am also a rocket scientist!

I would suggest that a slightly more approachable way to view an RTOS for MCUs is a library that sits on your bare metal that takes primary responsibility for efficiently dividing up available resources across multiple task functions.

An RTOS will usually provide a well documented SDK with support for memory safe queues, semaphores and message brokering.

Think of it as a software enforced contract + best practices to ensure that you get stable, predictable timing loops without ugly polling and blocking.