update: not resolved, but bandaid found
cropping all of the images to make squares, then enabling: “Shrink slideshow’s height when width shrinks” and then making the ratio 1:1, mitigated the problem. However, I lost the option to adjust the height…so while the cropping itself helped to make the images appear bigger (and not warped), as they are more zoomed in, they are not yet at the desired size.
Also, I have images that I would prefer not to be squares…so the initial question above still stands, but for those in the same boat looking for a temporary solution, you might consider this mitigating fix…
