I undertsand that you want to achieve the desired camera view where the camera focuses on a specific face of a 3D object and aligns with the face's normal.
You need to adjust the offset value to ensure the camera is far enough from the triangle to view it comfortably and the choice of the up vector can affect the orientation of the camera view. So, ensure it is orthogonal to the normal and not parallel to it.
Also, you can adjust the camera view angle according to your need by using "camva" function. Please refer to the below dcoumentation of "camup" and "camva" to get more information: