Error when deploying on Heroku

Following the migration steps to 4.1.8 seemed to get the production server working. So I’m considering this issue resolved but I’d really like to understand how to resolve the errors / warnings I’m still getting in the build logs.
https://docs.strapi.io/developer-docs/latest/update-migration-guides/migration-guides/v4/migration-guide-4.0.6±to-4.1.8.html