Unexpected Error when trying to access the storage field settings of the mailchimp subscription field (error log: simplenews_subscriber entity type does not exist)

Problem/Motivation

When I try to access the storage settings of the mailchimp subscription field (https://root.com/admin/config/people/accounts/fields/user.user.field_newsletter/storage)

Error Log

Drupal\Component\Plugin\Exception\PluginNotFoundException: The "simplenews_subscriber" entity type does not exist. in Drupal\Core\Entity\EntityTypeManager->getDefinition() (line 139 of /home/root/core/lib/Drupal/Core/Entity/EntityTypeManager.php).
What does the Simplenews has to do with anything anyhow? Does Mailchimp rely on Simplenews?

Steps to reproduce

• Install Mailchimp (manaully or with composer i tried them both. theoretically it could be a problem i dragged with me due to the former manual installation)
• Add a newsletter field to the user profile
• Try to access the storage settings of said field (to set merge tags i assmue like it was for druapl 7?)