We are experiencing the exact same reports with our Safari extension ever since migrating to Web Extensions. It appears that Safari is spinning its wheels with each open of the pop-up for about 1.2+ seconds or more with each click, before even making the first request to fetch index.html and render. See for reference (also a link in there for a timeline recording): https://github.com/bitwarden/browser/issues/1732. Has there been any progress on this issue or movement on the feedback issue(s)?