When setting the IsLooping property to "False" through SpinnerStyle property, the infinite looping while scrolling is not disabled.
<ContentPage.Resources>
<Style TargetType="telerik:RadSpinner" x:Key="spinnerStyle">
<Setter Property="IsLooping" Value="False" />
</Style>
</ContentPage.Resources>
<VerticalStackLayout WidthRequest="300" HorizontalOptions="Center">
<telerik:RadDateTimePicker x:Name="dateTimePicker"
SpinnerStyle="{StaticResource spinnerStyle}"
MinimumDate="2020/01/01"
MaximumDate="2026/12/31" />
</VerticalStackLayout>