I have seen a few questions about this on the internet and have also experienced some frustration with it myself. In Bookmarks Manager if you clock ‘Sort by Name’ once and don’t click undo that time, the bookmarks are sorted by name permanently with no option to change the list format.
Though not a programmer myself, I find it is likely not the most difficult thing to add another Sort button to allow sorting by date.
Hopefully this issue will be solved in the near future with the help of this request.
Thank you for your time and understanding.