Wrong.
Wrong by a country mile.
Buddhists have never been more than about a 15% minority in VietNam, even combining the North and South.
The vast majority of VietNanese, primarily of the Kinh (Viet) ethnic group practice a folk religion that is based on ancestral and nature worship.
Buddhists simply appeared to be prominent in that they were used as shills both by the Communists and the foreign (including American) press.
LOL!
Whenever my wife was asked her religion, she said ‘none’!
It was poison to be an open Buddhist during Diem’s reign.
Now crawl back into your hole.