Hello @chrisgoogo,
Although the Lightning Design System Plugin is no longer developed (it was Archived in August 2023) this seems to be a bug affecting only the spinner animation.
When you select libraries from the plugin, the spinner will keep going, but the libraries are properly installed and you can add the symbols they contain, take a look at the screenshot below.
However, since the plugin is no longer developed, please consider that the libraries may be removed by their owners without notice.