Bookmark all open tabs in mobile safari
Tyler Brook, the article you link as a solution is for a computer type of device and not an iPhone or mobile version of the browser. The mobile version has a more limited menu.
 I have the same question and am hitting the same wall.
So far I have to email my self links to get the open pages to a non-mobile device(with a bigger screen for my old eyes ). 

The iOS 13 update is testing a new function to do exactly what you seek. 


https://www.macrumors.com/how-to/bookmark-multiple-open-tabs-safari-ios/