Thank you all for the help. In my search, the closest I could find is this:
https://www.daz3d.com/imagine-this-turtleneck-tank-and-skirt
John's "Cute for Genesis 2 Female" suggestion is also very close to the asset this dev used. Unfortunately, both assets suffer simply one crucial detail in their meshes that don't align with what the dev used in the screenshot I provided.
It confuses me greatly because this dev (for context, the dev for Midlife Crisis, a VN game now abandoned) used many assets straight out of the box with virtually no modification. Why this shirt asset for one of the female characters is so particular, I do not know.
I suppose I will just have to edit the meshes of one of these Genesis 2 Female shirts to match more closely what is in the screenshot... oh well.
Edit: Also 3Demon, close but no dice. The dev used Second Circle's Lauren for Genesis 8 Female as the base for this character; her name is Christine. With virtually no modification made to the morph or textures, might I add.