I am upgrading our Portal for ArcGIS, ArcGIS Enterprise, including both of our web adaptors. However, I believe I made a mistake installing the web adaptor and needed to start over. So I uninstalled the web adaptor, and then began the reinstall process, but now I'm running into an error message:

I would rather not choose a different web adaptor name in case this continues to happen LOL...so then this begs the question, if I have already uninstalled the previous web adapter then how can a web adapter with that name continue to exist on the default web site? A second question would be, "how does one then remove the default web site?"
Thanks