Great question! Thanks for pointing this out. This is absolutely something that should be in place as a user-configured setting so you can choose whichever format you prefer.
Obviously, the component is pre-set to always start the week on Sunday, despite the fact that there are differences in what is “standard” depending on where people live. American calendars typically start on Sundays while European calendars typically start on standard.
In short, we’ll add this to our list of tasks to do once we support the ability to provide user-configured and chart-specific settings and preferences (which is a work in progress right now).
Thanks for bringing this up here on Cognite Hub!