There is a style of hijaab worn by wearing the headscarf as a "turban". Typically but not always the lower part of the ears are displayed with earrings (earrings aren't tucked under the scarf). The neck is not covered by the headscarf so a Turtle Neck top is worn to cover it. Is this style permitted by any scholars in the Sunni world? Doesn't seem to make sense to wear visible earrings in front of non mahrams as they are a form of attraction for them no?
It's impermissible in two ways:
A woman's ears are ordinarily considered part of her awrah and thus it is impermissible to expose them to non-mahram men. Example fatawa making this claim:
While wearing the ‘hijab’ (to cover the head) it is farz (essential) for a woman to cover the ears. It is haram (unlawful and sinful) for women to show their earrings while wearing their hijab. -- Mufti Waseem Khan, sourced from IslamQA.org (Hanafi, Sunni)
The fuqaha’ are agreed that a woman’s ears are ‘awrah and it is not permissible to show them to non-mahrams. -- Islam Q&A (Salafi, Sunni)
The ears are not considered part of the face as far as the obligation of covering the ʻawrah (body parts that must be covered as per the sharee'ah) is concerned. The woman is obliged to cover the ears as part of the head. -- IslamWeb
The ears are not part of the face, therefore it is obligatory to cover them. -- Ayatollah Sistani (Shia)
Exposing one's adornments to non-mahram men is further impermissible:
And tell the believing women to... not expose their adornment except that which [necessarily] appears thereof... -- Qur'an 24:31
However, I would not interpret wearing earrings (whether or not she's exposing her ears) as an attempt to attract men. There's plenty of other reasons that a woman might want to wear earrings, e.g. expressing her femininity. We should assume the best in other Muslims and avoid suspicion.
There's debate as to what constitutes hijab. As an example, Lamya Kaddor (whose scholarly credentials have been contested in the comments) regarded the "headscarf is obsolete". At worst, she is merely mistaken. Likewise, it's possible that the women who wear this turban-style hijab believe it is permissible and are, at worst, mistaken. (The point of this is: let's go easy on our Muslim sisters who wear the turban-style hijab.)