Autodesk enhanced the 3D views with the 2021 update, but I have had issues with my 3D views causing my model to crash. While working in 3D I'll sometimes get the error "Revit could not draw the contents of this window, this window will now be closed" and the 3D view closes. When this happens I get the same error for any other Revit views that I have open, until all my views are closed and Revit quits out of my projects.
This never happened in previous versions of Revit, and I honestly think that the realistic 3D views looked better in the old versions after tweaking the graphics display options.