I have Woocommerce on my install, and it’s working via API now. I changed mail.yml to default. Sorry I thought it would work straight out for you like it did for me. Hopefully you can figure it out soon. I was convinced our issues are related but possible not.
If you have the option of downgrading to ipv4, here’s a thread I’d done on that a couple years back: Composer.lock & Packagist Issues