Shortlink plugin can access shortened links.
Links registered in Google Search Console (Webmaster) must still use the original link, this is because the shortlink plugin is loaded completely using JavaScript.
Example :
You must register the original link :
https://blogname.blogspot.com/2021/06/what-is-seo.html
instead of the resulting shortlink :
https://blogname.blogspot.com/what-is-seo