Honestly, on a meta level, how AFO ends realizing he failed to sever his humanity could be a fitting defeat, especiallysince it was a redeeming quality that wasnt exactly open and shut nit mitigating...
Had it been paced properly. The pacing was atrocious, and I'm not talking about just this but the actual final battle. AFO returns from the dead and then the story just zooms to the end when he gets bodied after just 5 chapters... that's it? The entire thing was too rushed to not feel anything but half-assed, and his defeat in general feeling very anticlimactic. Any and all momentum was pretty much killed. If the anime should adapt it, which I'm sure it will, they better do what AoT did and try slow the pacing to bake everything properly.
On the bright side, at least the story doesn't bother to forgive his actions despite this... as they should.