And then

later I stumbled upon Shops:

https://socialhub.activitypub.rocks/t/shops/5354

https://codeberg.org/potato/shops

And I was curious, would Shops perhaps potentially work as a potential Fediverse alternative / replacement for Amazon?

The platform I use currently (hubzilla) has support for shops, but it works through its own zot protocol, but I feel this can be extended to activitupub. It is federated currently but only on the networks that support openwebauth. Maybe the technical minded would know better about this.

You should read their project page and blog. I mean I don't own any crystal ball, I can't look into the future and see if it's going to succeed... It speaks ActivityPub. So it is the Fediverse. And it is a shop... Or better: It might become one. Because their progress meter shows something like 25% done. Currently it's just some early computer code and they need to invest a lot more time before it's ready to do anything.

I doubt it's gonna "replace" Amazon, though. I mean Free Software alternatives rarely replace multi-billion dollar companies... But if they keep at it, it might become an online shopping platform. And maybe one day, you can buy something there, or sell your Etsy stuff via "Shops". Or maybe they lose interest, start a new hobby, finish school and don't have time for this anymore and the project goes nowhere. I don't think we can tell.