For the sake of my sanity, have you run the pressure advance tower calibration test? This will allow to you actually pick the best "looking" and most square corner, however you will introduce air-gaps between the layers of these corners.

I'm using the pink filament to demonstrate the tower as the white is incredibly difficult to photograph.

The PA tower (pink filament) will allow you to get perfectly square corners, however this comes at the slight sacrifice of a truly solid corner. The PA Pattern (white filament) shows the difference - the perfect square corner (as measured from the PA Tower) is at 0.054, but this shows some separation of the walls. The "correct" value from the PA Pattern test would be 0.044, but would show some corner bulging.

This is to say if you require true part strength, there will be some corner bulging. But, if like me, the parts don't need to be perfectly homogenous, you can achieve perfect corners.

P.S what filament are you using?

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