> Anybody have a good coding model (it's whatever language Atmel Arduino uses, by default) that runs on a 5070Ti, best?

Atmel Arduino is mostly assembly (rarely used and assembly is generic to everything) and C. But you can’t use the usual C libraries because they are tailored to OS like Linux or Windows and the hardware those run on (i386, amd64, arm,…). That’s the primary constraint you need to implement in whatever LLM tooling you’ll be using. The majority C examples are about Linux or Windows API, not the simpler AVR standard library (the gnu one).

Other than that, on Linux and Windows, the hardware is abstracted away. For Linux, You don’t interact with the keyboard and mouse, you use libinput/x11. You don’t interact with soundcards, you use alsa/pulseaudio/pipewire,…. With AVR devices, most abstractions are only one layer deep and mostly help to avoid dealing with the boilerplate of bus protocols. You spend more time with datasheets and diagrams than with code.