An alien can come to Earth and use its UFO compute to mine bitcoin if it wanted.

Not if it wants to win a block reward in any reasonable length of time.

First of all it would have to set up manufacturing to produce 7nm asic chips generating the SHA-256 algorithm.

Someone in their garage could come up with a vastly superior way to compute hashes and mine bitcoin.

This just means your hypothetical Tony Stark gets richer. It doesn’t help the aliens you invented earlier.

Large mining farms could be banned and made illegal and smaller operations can instantly become profitable again.

You still need human interaction to buy the necessary mining equipment.

Face it. Your idealistic objections to PoS apply equally (if not more so) to Bitcoin.