Converting Blender model to unity (drag drop) causing wrong edges (nonquad, different from original model, which was quad)

Converting Blender model to unity (drag drop) causing wrong edges (non-quad, different from original model, which was quad).

My Blender model changes edges when imported from a blender file into Unity/ProBuilder.

What am I doing wrong?

Unity version 2021.2.4f1
Unity Pro Builder version 5.0.7
Blender version 2.91

You should export the model as an .fbx file because they are said to be the best file types for converting blender models to unity.