The main problem with the idea of dividing Syria into a Sunnistan, Alawite Homeland, and Kurdistan is that the Turkish proxy, HTS Al Qaeda, would rule the Sunni area as the Taliban rule Afghanistan - by committing constant atrocities against women & minorities.

Another huge objection to the idea is that it relies upon the ethnic cleansing of whole towns, villages, and regions, as we've seen in Kurdish majority Afrin, and Shi-ite majority Nubl & Zahara, ethnically cleansed by the Turkish Army and its proxies.

For the Americans to back the idea of a Sunnistan in Syria, administered by Turkey's HTS Al Qaeda proxies, the USA would have to promote AQ as a suitable partner and sanction the eradication of ancient Christian communities finding themselves inside the Turkish / AQ area.

Ethno / Sectarian / Theocratic states are not viable or morally justifiable. The idea is based on discredited notions of race & obscurantist dogmatism. Modern states are diverse, pluralist, & tolerant, respecting the rights of women & minorities. We do not need a 'Taliban-lite.'