jailhouse VS embedded-trainings-2020

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 must admit I've never used it for anything but tutorials yet (kids resulted in a lot of personal projects shelved), but Rust has an amazing and rapidly developing embedded ecosystem. A good starting point to get an impression of it might be training materials from Ferrous Systems 1, 2 (feel free to pay for the training itself if you feel like it's worth it for you of course). There is an embedded working group for Rust, Knurling project to improve tooling and even an attempt of Rust standard certified for safety-critical application.