I am torn -- while I love the bitter critique of std::simd's nightly builds (why bother with any public release if it is never stable?), I cringed at the critique of "(c)urrently things are well fleshed out for i32, i64, f32, and f64 types". f64 and i64 go a long way for most numerical applications -- the OP seemed snowflaky to me with that entitled concern.

Not supporting other types (particularly smaller ones) can be quite limiting on portable SIMD, especially when it doesn't support AVX512 either, but those are certainly a good core group - just not the whole story. Regardless, I'm not sure how painting the OP as an entitled snowflake helps anything over just asking the question.