I think a properly hand tuned AGENTS.md with proper tooling instructions and a single PLAN.md goes a long way especially if you add directives in AGENTS.md to keep the PLAN.md always updated with journaling.
There is no way we are alone in this universe, what would really be a big deal though is if there are somehow able to traverse light years to reach us.
Yup, I own a Redmi 3S Prime for ~$130. It's a great value phone and doesn't lag. MIUI is extremely slick and easy to use. I persuaded four of my family members to go for Xiaomi phones and they couldn't be more happier.