PSD Corrupted from Power Loss - 8BPS Header Intact but Black Composite

My PC lost power exactly as I was saving a large catalog. The file is 784 MB. I cannot open it in Photoshop, Photopea, or third-party repair tools.

I verified with a hex editor that the 8BPS header and XMP metadata are intact, so it is not filled with zeroes. However, when I used ImageMagick to extract layer [0], it output a solid black PNG.

Can anyone with advanced hex/scripting knowledge see if the individual layers are still recoverable?
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