Our company is open from 6:00 PM to 5:00 AM. Can the calendar display only these hours without splitting at midnight?

Open the resource settings. Check the Visible hours option and specify the desired start and end times.

You can also set the desired time range in the manager's table. Open the table settings. Select the period Yesterday, Today or Tomorrow. Check the At specific hours option. Then, set the start and end hours.

Here is an example of how the widget appears to clients in action: