Maybe a little weird question but do you maybe know a smart watch that can run rust? I got running Egui on my Galaxy Watch 4 with WearOS and I'm thinking if any other watch (other than Galaxy and Pixel) can do that?
Anything that can run C++ should be able to run Rust if you use the LLVM backend, perhaps except when a watch uses musl libc and you rely on some glibc-only call in your program. afaik the only physical devices shipping with musl are car infotainment systems based on l4 kernels and networking hardware (OpenWRT).
no-std Rust has no run-time dependencies of its own.
std Rust runtime-requirements are basically libc, a heap allocator, and a threading library. Many implementations on many OSes are already supported, including musl on Linux. And what's not supported can theoretically be so in the future.
Code generation at build-time is dependent on LLVM, with cranelift and (soon) GCC available as not fully mature alternatives.
3rd party code/crates may impose additional requirements.