Thanks for your response, Vince.
So, to verify, the only thing affected by the way you set up your time line (2k, 4k, etc…) is the Program and Source project frames, i.e., the size of the frame you are monitoring while editing.
Also, for anyone using this post for help with their own project, if you have set up your time line with a resolution smaller than your original files, don’t forget to right-click on the clips in your time line, and then select “Scale to Frame Size” so that your clip is cropped correctly in your Program window.