Setting the Visibility of LineSeries3D to Collapsed works initially. However, once the Visibility is set to Visible, changing it to Collapsed doesn't hide the polyline visual.

To work this around, add/remove the series in the chart's Series collection, instead of changing its Visibility.

Implement a provider allowing the customers to create dynamic number of series.

Allow stacking of series one over another.

Check the attached project for a possible approach for working this around.

Implement Crosshair to show the mouse location(X,Y,Z Axis), depending on that where it is on the plot area.

This is the same as the Conversion API in the ChartView (2D).
https://docs.telerik.com/devtools/wpf/controls/radchartview/features/conversion

The API should allow you to provide 2D coordinates on the screen and return the associated coordinates on the chart axes.

Add a property that allows you to get the actual range of the LinearAxis3D when the Minimum and Maximum properties are not explicitly set. The same feature is introduced in the RadCartesianChart axes (like LinearAxis) via the ActualRange property.

as I implement SurfaceSeries3D, as well as many, for layered forms, such as provider series

To work this around use DisptacherTimer instead of Task.Run.

Create a 3D range bar series. Something like the RangeBarSeries in the 2D chart.

This issue is related to the SurfaceSeries3D. Originally when you have a data point with its ZValue set to null, the chart will create a gap on the surface. This always happens. However, on some machines the null values are treated a bit differently by the renderer and a triangle is drawn from the points around the null data to the center of the viewport. This leads to an unexpected visual glitch.

Add lines series support in the new 3D Charts.
A Line series is pretty similar to PointSeries3D with a Line [a tube] that connects points.

This can be integrated in the Chart3DCameraBehavior. The user should be able to pan around the viewport. And also to zoom based on the mouse position. Currently, the zooming is based on the center of the viewport.

Add 3d chartview IsInverse axis options.