OK. I have 14.1.2. When I searcher "Sleep", On the left, results are Energy Saver, Desktop and Dock, Displays, ... On the right Energy Saver is presented with options and descriptions of what to expect. Read through these, both right and left panels and see if any will help your "Sleep" mode reviving. You should be able to change the sleep mode with these.
Sometimes these problems are just learning experiences.