Aphrodite is mythological, Helen of Troy is ambiguous like King Arthur or Robin Hood. Likely mythical.

As a goddess, Aphrodite can appear as she wants, and often changes how she looks.

Helen, while human, is always described as "white armed" or "fair haired", no mention of a unibrow.

https://www.thoughtco.com/helen-of-troy-iliad-of-homer-118918

If you want an example of a woman considered to be attractive with a unibrow, you really don't have to look any further than Frida Kahlo.

She had multiple lovers in her lifetime, men and women, and her self portraits often depict her with an exaggerated unibrow and mustache.

Her photographs don't necessarily agree, but obviously she considered it a unibrow if she put it in a self portrait.

One of 55 self portraits, 1940:

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Photograph, 1940: