Thank you for your feedback! After discussing with the relevant team and reading through your feedback, we agree that being able to customize calendar widget colors is an important feature. While we are planning on developing this feature in the future, a the moment we are focusing on other areas of the platform and do not have a definite date for when this feature will be released. We will make sure to keep you update on the development of this feature.
Learn more about how our feature request process works: All you need to know about our new Feature Request process