If zero of potential energy is not taken at infinity, total energy and potential energy of electron change but not kinetic energy. Why is that so?
The zero of PE is at infinity actually. A charge at rest would have 0 energy at infinity. That's why bounded states have negative energy. For the hydrogen atom, the electron at its fundamental level is $-13,6 eV$, negative because it would escape if it had 0 energy, just like any orbit.
Plus, KE depends on velocity, not on PE.