jailhouse VS the-backdoor-factory

You could run it inside something like jailhouse hypervisor (https://github.com/siemens/jailhouse) if you want to give it direct dedicated "baremetal" access to hardware. You could do this inside of a buildroot linux image. This would need a customized simulator.

Yes indeed, and Siemens even has their own hypervisor: https://github.com/siemens/jailhouse

Yeah, I think that is what something like https://www.toradex.com/computer-on-modules/apalis-arm-family/nxp-imx-8 is useful for, where it has a separate core. Or even on linux you can use isolcpus to get pseudo-isolation. There are also hardware hypervisors like Jailhouse (https://github.com/siemens/jailhouse) which can completely isolate hardware resources and I suppose might prevent the GPU from causing an issue with realtime task. But this definitely affects ease-of-use and probably requires a reduced feature set in the language (no dynamic allocations) and lots of unsafe code.

I don't think this argument holds much substance. FOSS developers are absolutely not lost without the source - they just share the fruit of their labor under FOSS licenses. In fact there's a good chunk of work being done black-box style: WINE, many of the drivers, game modding, hell here's a random FOSS binary patcher[0]. So FOSS developers don't seem to be lost without the source.

[0] https://github.com/secretsquirrel/the-backdoor-factory