How to Fix Method Navigation in Unity Project Scripts Opened in Visual Stuido

The cause is that the Unity project is not associated with the Visual Studio you are using.

Just follow the steps below:

Open the Unity project
Select Edit –> preferences in the menu bar
On the left side of the window that pops up, find and select External Tools
In the right-hand pane, find External Scripts Editor and change it in the dropdown, selecting the Visual Studio version you use
Close the settings window

From then on, whether you open the project from Unity or right-click the Unity project in File Explorer and open it with Visual Studio, script methods will navigate normally.