Setting up contactless payments with Pixel Watch

final

Hi,

I have been searching some threads about using Pixel Watch for payments. I understand it works with GrapheneOS although I am unsure on the clarifications due to different setups the users have.

Do you need to be on the Stock operating system to link a card to the Pixel Watch similar to requiring the stock OS to use it on your phone, or does it work with Sandboxed Google Play?

Thanks!