For the theory to match up, the Universe would need an acceleration as tiny as 6,79×10⁻¹⁰m/s^2 to reach speed of light after 14bn years

it means an acceleration of 0.67 nanometer/s^2 kek

I don't think that would fit a what we imagine as Big  Bang but just a lil' pathetic bang relative to ants or viruses :)))