There is an all-in-one article including every part from this series (if you want prefer to read it all at once instead of "by installments")
Nothing could be further from the truth. Accessibility doesn't determine if a website is ugly or not. There are beautiful, accessible websites and really ugly non-accessible websites. Accessible websites will be as ugly (or as beautiful) as they are designed to be. Like any other website!
This myth has gone a long way. It has existed since Web Accessibility is a thing (which means, basically since the beginning of the Internet) and it is rooted in a misconception. Before, the idea of accessibility was linked to no styles, no animations, no images, no videos... no nothing. A bland, dull, ugly site. But that doesn't have to be the case.
Some of the accessibility requirements will indeed limit the creativity of designers and developers (e.g., sometimes finding an accessible color palette can be a challenge), but there are many tools online that will help with that. Plus, the different standards have evolved to include many accessibility features.
We need to ditch the idea of building a website and then uglifying it to make it accessible. That's an old-school mentality. Accessible websites can be visually striking, animated, fun, interactive sites from the start. And good designers are doing a great job at infusing inclusiveness and accessibility out of the box.