That was an objectively terrible blog post. But, because I was curious, I actually went digging into the docs for it and it seems that "WCSM" only supports fetching from S3 Compatible origins, which those pre-signed Takeout URLs are not: https://docs.wasabi.com/docs/wcsm-for-data-migration

Hypothetically one could trick the Cloudflare workers into exposing those Takeout URLs under fake GetObject request-response handshake, but ... what a lot of work just for Wasabi