I like Swift a lot but Apple seems to be focusing on cross-platform within their ecosystem only, the fact that it runs elsewhere almost feels like a side effect

I like Swift a lot but Apple seems to be focusing on cross-platform within their ecosystem only, the fact that it runs elsewhere almost feels like a side effect. If your goal is sharing some cross platform code then I feel like you're better served by Rust / Go / Kotlin Native / C++ as these languages are making / have made and effort in that space.