The different effects don't seem to work properly. For instance, any of my transform effects don't seem to be applied properly, and any crops that I made did not work properly in the final render. Some images, videos, and title clips alike are missing, or rendered as a white image. Needless to say, most of the video is rendered incorrectly, despite the preview showing otherwise.

Ok, what version of Kdenlive and on which platform?

For instance, any of my transform effects don't seem to be applied properly,

Ok, what happen? What are you trying to do? You apply the Transform and what doesn't work? Rotate, Opacity, Animation, Everything?

and any crops that I made did not work properly in the final render. Some images, videos, and title clips alike are missing, or rendered as a white image.

Be sure your assets still at the same folder during the entire processes, but assuming that you said: "title clips are also rendered as a white image" so...

Needless to say, most of the video is rendered incorrectly, despite the preview showing otherwise.

The problem is probably during the render time, it helps if you send us the information requested by bartoloni and also your desktop settings and render settings