ToaruOS has an ARMv8 port: https://github.com/klange/toaruos and Serenity has an ARM and RISC-V ports: https://github.com/SerenityOS/serenity ; although I think you would call them Unix-like.

Haiku has tier-2 ports to ARM, RISC-V, and SPARC: https://www.haiku-os.org/guides/building/port_status

ReactOS has an ARM32 port but the ARM64 one is not usable yet.

Skift apparently runs on ARM and RISC-V: https://skiftos.org/