Currently, RadTimePicker offers a Value property, typeof(DateTime?) even though the control is designed to manage time values.
With releasing .NET 6, there is TimeOnly type which would be more appropriate for managing time values:
https://devblogs.microsoft.com/dotnet/date-time-and-time-zone-enhancements-in-net-6/
For example:
//from 22:00 till 07:00 the next day.
this.radTimePicker1.MinValue = DateTime.Today.Date.AddHours(22);
this.radTimePicker1.MaxValue = DateTime.Today.Date.AddDays(1).AddHours(7);