Weird display issues: zebra stripes, triangles around edges

You’re seeing Z-fighting due to the huge distance from camera to model. Switch the camera to Perspective and hit Zoom Extents.

Generally it’s better to do your modeling with the camera set to Perspective anyway.

You really should get in the habit of maintaining correct face orientation. The vase majority of the faces are reversed in your model.

You should also learn about using groups and components.