We do not, in fact, have less brain than hominins millions of years ago. We do have less than our immediate ancestors 100,000 years ago. Your very intelligent

We do not, in fact, have less brain than hominins millions of years ago. We do have less than our immediate ancestors 100,000 years ago. Your very intelligent AGI would most likely have no interest in seeding anything on Earth. It might reasonably be curious about our ecosystems, but disturbing those would reduce that interest.