The creation date is indeed pretty strange to see! But, I think the over 300 MB size of your file might be more related to the slowness. Run (download if you need to) the Polycount add-on to check how heavy your model is.
The creation date thing is a little worrisome... suggesting perhaps some file system corruption. I'd do a repair disk on the volume holding that file to at least locate/fix the most obvious disk issues.
Age of hard disk?
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AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB