Is there a way to make admin new reservation arrival time fixed?

My customer wants to enter new reservations through the dashboard but she does not want to bother with the arrival time and leaving time. I already disabled those options on the user form side as it is provided but is there a way to do the same with the admin side of things?

Or, is there a way to hide these time selectors on the admin side of the plugin?

No, there is no way to change the admin form.
Regards