This ones not too bad, it's not strictly a smiley though. https://www.codeoftheancients.com/glyphlibrary/glyph/U406

When you look under 'happy' they mostly seem to link to concepts of ripening, harvest, blooming and sweet things.
https://www.codeoftheancients.com/dictionary/egyptian/term/happy

Seems like they also could spell it out sometimes with multiple characters, which sort of surprises me.