This is a different stuff.
I would say your example is a ported solution from FreeRTOS (https://www.freertos.org/RTOS-Cortex-M33-LPC55S69-MCUXpresso-GCC.html)
In the NXP SDK you have tfm based examples like tfm_demo_ns & tfm_demo_s, unfortunately the NS part is a bare-metal example.
So my main problem is a non-secure FreeRTOS part and I'm still looking for a such example.