In 1911, Einstein discovered a reason for the blueshift of light in the increase in energy in the gravitational field.
The shortening of the length scale** also causes a shortening of the wavelength of light. Since this is measured using a local scale, no blueshift is found. However, because the light comes from a different time frame and the light does not change its frequency on its path, more amplitudes are displayed on the meter in the dilated time.
Therefore, no energy is needed to explain the blueshift. The same applies to the ""Einstein elevator.".Nothing changes in its system (as long as it is not stopped). Energy equals mass, so mass would also be an illusion. "Ghost mass" cannot be found locally. Perhaps all mass is energy mass or "ghost mass." In this theory, most of the energy is the distance between the massive objects. For an infinite number of particles, this energy is infinite for each particle. The usual negative potential energy lacks a constant. This constant is the maximum kinetic energy for force-free motion, i.e., without adding energy.

*Book "Grundzüge der Relativitätstheorie" page 49 by A.Einstein.
**"Snow Globe Theory"

Ludwig Resch