Photo-electric effect
A light particle moving towards a surface cannot (by collision) force an electron particle to move away from that surface.
A light wave can instead make interference with a bound electron and thereby force the electron to escape, and this process is reversible, so electrons cam also be captured by atoms and generate waves. Capturing electrons can generate X-rays.
Compton effect
This effect can be explained by light waves absorbed in an electron escape and later emitted in an electron capturing. Two processes with secondary emission of longer wavelength. Longer wave length means: not a scattering process.
Waves can explain everything and particles for light are not needed.
Einstein did not understand the photo-electric effect.
John-Erik