This myth is based on the technology limitations that existed years ago. At that time, the limitations were much more prohibitive for designers and text-only was often considered the best way to achieve accessibility. Today, accessible websites can be rich with images and videos, as long as you include alt text and captions.
It is true that accessibility places a few design limitations on websites. But that doesn’t mean the only alternative is an ugly site. It just means you might have to make a few adjustments. For example, you might not have your first choice of font size, or your color palette might be a little constrained. But there are plenty of examples of beautifully designed accessible sites.