Technically you just described an M-series MacBook. Even if you don’t like the BSD-derived genuine certified UNIX that is macOS, they are also supported by OpenBSD and NetBSD. Work is also underway to add support for FreeBSD.

https://www.openbsd.org/arm64.html

https://wiki.netbsd.org/ports/evbarm/apple/

https://wiki.freebsd.org/AppleSilicon