The universe does not have a universal beginning or ending for all matter. Rather, the universe has a beginning, duration and ending based on the size of the body which experiences it.
Dark energy is a double-arrowed force in which one end of the force (gravity) repels the other end of the force (expansion). The force which resists gravity is referred to as expansion or expansional force. The expansion of the universe exerts gravity in the opposite direction to the expansion, forming all non-space which we observe and experience in the universe.
This is according to my new theory, the Theory of Space-Matter (https://drive.google.com/file/d/1x_JSDpKy4pey2wHF3k9ipuDpt_hUaLZK/view?usp=sharing). The Theory of Space-Mater consists of three sub-theories: The Theory of Infinite Dimensions, The Theory of Relative Displacement and The Theory of Gravitational Thrust.