Mainly, if a source is updated, views should also be updated … I opened a bug report (https://gitlab.kitware.com/paraview/paraview/issues/19553).
In the python shell, you can use the command Update() on the choosen view. (see GetActiveView() and GetViews())
Concerning the update interval, you can add a python attribute on the live source to compare with current time and update each n seconds. See this thread : update automatic data input