@Gene1
How do you want to submit the events? By EditForm or Patch function?
''I also would like to have the end date be the same as start date. However be able to put start time and date.' - What does this sentence mean?
If you want to use EditForm, try to add judgment condition to OnSelect property of submit button, if the schedule is repeated, show an error notification, else then submit the form.
ClearCollect(ColLocation,Filter('Calendar Name',Location =Location_DataCard1.Update ));If('End Time_DataCard1'.Update in Filter(ColLocation, 'Start Time'='Start Time_DataCard1'.Update).'End Time',Notify("Schedule Repeated",NotificationType.Error),SubmitForm(FormName))

Sik