I've seen multiple SoCs from China that integrate a high performance Linux core and a smaller MCU-like RTOS core into the same die. SG2000 being one example.

Pretty clear to me that they're aiming at drones, 3D printers and robots with that.

Not just Chinese companies, Ti has done this forever with their Sitara SoCs. This is the chip in the beaglebone. The chip includes two PRUs which are microcontrollers that run at 200mhz and share memory with the rest of the system.

TIs latest version of it (AM625x) has four A53 cores, one PRU, and a Cortex M4F. It is similar in performance to the Qualcomm chip in my own benchmarks

Feels like everyone is doing that sort of thing these days, it is very common to see Cortex M series core integrated into big SoCs. Quickly checking TI, NXP, and ST all have M4 (or similar) cores integrated to their SoCs