Ok, so this feat was originally rated as High 3-A, but because changes to the tier it no longer is, so a new tier is needed.
《That’s right. We were hurled to beyond space and time due to Yuuki’s attack. The lifespan of the planet has already ended a long time ago, but the collapse of the world hasn’t yet been reached. From that I deduced, Yuuki probably couldn’t destroy the world itself yet. When he was at the phase where he destroyed the celestial bodies as well as the space-time continuum, I presume that Yuuki’s lifespan had come to an end. However, I can’t judge whether his wish was fulfilled or not. After that, we wandered around as we drifted in the space and I witnessed the end of this universe.》"
So, destroying all celestial objects would mean that Yuuki destroyed all moons, all planets and all stars, with the last objects being those that obvoiusly give the highest results for AP [Not counting black holes because those are impossible to normally destroy]
.Since Yuuki destroyed all celestial object, it's safe to say he would have destroyed even the toughest and densest of stars, so i'll calc how much energy he would need to destroy the densest we know a star can be, a Neutron star.
GBE for stars is (3*G*M^2)/(r(5-n))
The largest neutron star, a pulsar, is 2.17 Solar Masses with a diameter of 15 miles
AKA a mass of 4.34E30 kilograms and a radius of 12070.1 meters.
Assuming a n (which can go from 0.5 to 1) of 0.5 (DMUA told me to use this value)
G is a constant of 6.67408x10^-11
(3×6.67408x10^-11×4.34E30^2)÷((5-0.5)×12070.1) = 6.9433449e+46 joules, approximately 694 Foes and Solar System Level