arm64 CPUs support NEON unconditionally. arm64e implies the armv8.2 and armv8.3 extensions (but not SVE), notably half-precision arithmetic and interleaved comp

arm64 CPUs support NEON unconditionally. arm64e implies the armv8.2 and armv8.3 extensions (but not SVE), notably half-precision arithmetic and interleaved complex ops. You generally should not need to do runtime selection.