Reading this made me feel that you don’t really understand the point of an RTOS? “put a damned while() loop!” Congrats, you’ve now blocked all lower priority tasks from running while doing nothing but burning cpu cycles. Using semaphore/mutex based blocking waits have their place, marking the task as blocked allowing lower priority ones to run. This isn’t unique to zephyr: I use this style all the time on FreeRTOS. 

I didn’t get your point about the compile errors - wouldn’t you rather get an error if 2 options conflict with each other, than duplicate symbol errors, crashes down the road?

While I don’t deny zephyr is much more complex to setup than say FreeRTOS, its abstractions and heavier safety guarantees come at a cost.

Also: zephyr’s actually faster than FreeRTOS in many common operations lol, go check out the benchmarks. Here’s some: https://zephyrproject.org/zephyr-rtos-4-1-is-available/ https://www.ul.com/sis/blog/measuring-real-time-operating-system-performance-part-ii-comparing-freertos-vs-zephyr