It is worse than that. NetworkView is from the legacy networking based on Raknet. The one Unet replaced.
NetworkView is no longer a part of the most recent versions of Unity. It was deprecated several years ago. So long ago that the network solution which replaced it has also been deprecated a year ago as well. https://docs.unity3d.com/ScriptReference/NetworkView.html
Since Unity’s next network API is not yet ready, the solution is to choose a 3rd party networking library and switch to that. How to actually code the fix depends entirely on which networking API you choose - see its documentation.