You could use the TabView from the Xamarin Community Toolkit in addition to your TabbedPage . Here's how it works:
<Grid>
<xct:TabView>
<xct:TabViewItem>
<Grid>
<Label
HorizontalOptions="Center"
VerticalOptions="Center"
Text="TabContent1" />
</Grid>
</xct:TabViewItem>
<xct:TabViewItem>
<Grid>
<Label
HorizontalOptions="Center"
VerticalOptions="Center"
Text="TabContent2" />
</Grid>
</xct:TabViewItem>
</xct:TabView>
</Grid>
If you put a TabView in each of your TabBar contents you will be able to get the result you want.
In your case, it would be something like this:
<ContentPage Title="Tab 1">
<xct:TabView>
<xct:TabViewItem>
<Grid>
<Label
HorizontalOptions="Center"
VerticalOptions="Center"
Text="TabContent1" />
</Grid>
</xct:TabViewItem>
<xct:TabViewItem>
<Grid>
<Label
HorizontalOptions="Center"
VerticalOptions="Center"
Text="TabContent2" />
</Grid>
</xct:TabViewItem>
</xct:TabView>
</ContentPage>
<ContentPage Title="Tab 2">
<xct:TabView>
<xct:TabViewItem>
<Grid>
<Label
HorizontalOptions="Center"
VerticalOptions="Center"
Text="TabContent1" />
</Grid>
</xct:TabViewItem>
<xct:TabViewItem>
<Grid>
<Label
HorizontalOptions="Center"
VerticalOptions="Center"
Text="TabContent2" />
</Grid>
</xct:TabViewItem>
</xct:TabView>
</ContentPage>
If you want to see more about TabViews, there is a great article posted by Gerald Versluis, that explains it perfectly: https://devblogs.microsoft.com/xamarin/xamarin-community-toolkit-tabview/