I'm trying to update the extension we developed for Gmail using App Script, but I'm not able to update it, even generating a new deploy or updating the version of an existing deploy. Is there any additional configuration that I should do for the update to go to the marketplace?
I think your problem relates to the Marketplace SDK configuration for you app, you may need to access your GCP project for your extension and update the deployment Id to the target deployment in the Marketplace sdk-> App Configuration screen
https://developers.google.com/workspace/marketplace/enable-configure-sdk