I hate to sound like a broken record, but the RTk.gpio uses the STM32F030C8T6 and not the STM32F7 that’s referenced in the article you just linked to.
The STM32F030C8T6 is a low-cost Cortex M0 processor with limited peripherals and Flash memory:
The STM32F7 that’s referenced in the linked article contains a much more powerful M7 processor as well as more advanced/comprehensive peripherals and up to megabytes of internal memory and the ability to access external memory devices directly.
I should also point out that the Linux that is referenced in your article is running on the STM32F7 - I’m guessing it’s nommu Linux or some other cut down version of Linux that works without SDRAM/MMU.
Sorry, but there’s no simple route to have the RTk.gpio providing Klipper IO.
The range of “STM32” devices is very broad and encapsulates dozens, if not hundreds, of part numbers, all with different CPUs, memory size and configuration as well as different peripherals. You can’t count on one device in the family to be able to run the same software and interface to a host computer in the same way as another arbitrary device.