Hi,
<telerikMauiControls:RadDateTimePicker x:Name="fromDateTimePicker" HorizontalOptions="Center" VerticalOptions="Center" Margin="5,5,0,2" HeightRequest="35" WidthRequest="200"
Date="{Binding FromDate, Mode=TwoWay}"
SpinnerHeaderStyle="{StaticResource spinnerHeaderStyle}"
SpinnerStyle="{StaticResource spinnerStyle}"
SelectionHighlightStyle="{StaticResource selectionHighlightStyle}"
DisplayLabelStyle="{StaticResource displayLabelStyle}"
PlaceholderLabelStyle="{StaticResource placeholderLabelStyle}"
AreSpinnerHeadersVisible="True">
<!--<telerikMauiControls:RadDateTimePicker.DropDownSettings>
<telerikMauiControls:PickerDropDownSettings
FooterStyle="{StaticResource footerStyle}"
FooterTemplate="{StaticResource dropDowViewFooterTemplate}"
AcceptButtonStyle="{StaticResource acceptButtonStyle}"
CancelButtonStyle="{StaticResource cancelButtonStyle}" />
</telerikMauiControls:RadDateTimePicker.DropDownSettings>-->
</telerikMauiControls:RadDateTimePicker>
<ControlTemplate x:Key="dropDowViewFooterTemplate">
<telerikMauiControls:RadBorder BackgroundColor="{TemplateBinding BackgroundColor}"
BorderColor="{TemplateBinding BorderColor}"
BorderThickness="{TemplateBinding BorderThickness}"
CornerRadius="{TemplateBinding CornerRadius}">
<Grid ColumnSpacing="0"
RowSpacing="0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<telerikMauiControls:RadButton Grid.Column="0" HorizontalOptions="Center" VerticalOptions="Center"
Text="{TemplateBinding CancelButtonText}"
Style="{TemplateBinding CancelButtonStyle}"
Command="{TemplateBinding CancelCommand}"/>
<telerik:RadBorder Grid.Column="1" WidthRequest="1" Margin="2" BorderColor="#00B5DC"/>
<telerikMauiControls:RadButton Grid.Column="2" HorizontalOptions="Center" VerticalOptions="Center"
Text="{TemplateBinding AcceptButtonText}"
Style="{TemplateBinding AcceptButtonStyle}"
Command="{TemplateBinding AcceptCommand}"/>
</Grid>
</telerikMauiControls:RadBorder>
</ControlTemplate>
this code work before moving to RC3.
See https://www.telerik.com/forums/custom-dropdowviewfootertemplate