Been folding double and queen fitted sheets for a few decades, it is not really that hard.

• Pick a side (long or short)
• put the corners into each other, by folding in half (I like to put the “body” side of the sheets inside)
• put the 2 corners together (here you can put the sheet down to make the sides “nice” so they are square)
• fold in half until you can’t I usually get 3 folds (should be about as big as a towel folded in half 3 times on the shelf but taller)

Takes a few moments once you are proficient. All my sheets have had elastic on all sides