I'm modeling this truck and when I try to inset to make the side windows there is this weird shading/square in the size of the inset and the edges stay the same when trying to extrude too.
In your Bevel Modifier change Limit Method to Weight and tick Harden Normals. It also helps to increase the Segments field to 3 or 4. Go tab into Edit Mode and and select all the edges you want to bevel. Then press N to bring out the side bar. Adjust the value for Bevel Weight under Edge Data for anything between 0.5 to 1.0 you prefer. This will turn the edges to a blue color depending on the intensity.
Then tab back into Object Mode and right click select Shade Auto Smooth