Memory for Code space is only 121KByte

I can see that with Portenta based microcontroller (Machine Control or OPTA) , the maximum code space it 121KByte.

Why is it so small compared to the available 16MB onboard flah QSPI memory, 2MB Flash and 1MB Ram and additional 8MB SDRAM ?

I do not understand why there is such gap between code space and onboard memory available.

Is it a limitation of PLC IDE ?

No, this is the space Arduino dedicate to Axel runtime.