Aodai is not necessarily feminine. This is what man aodai looks like in Nguyễn dynasty : r/VietNam

Navy Blue, Blue or Black Hand Painted Vietnamese Traditional Long Dress for Men, Ao Dai Chu Re, Ao Dai Nam, No Pants A7

Áo dài - Wikipedia

Would other Asians think it is weird if Vietnam brings back Le Dynasty clothing and start wearing it like ao dai? - Quora

As per request, here is an album of the Vietnamese traditional dress ao dai : r/pics

Ao dai – The traditional attire of Vietnam

Ao Dai LoveToKnow

The traditional Vietnamese dress: Ao Dai- a symbol of the beauty of Vietnam

The traditional Vietnamese dress: Ao Dai- a symbol of the beauty of Vietnam

Ao Dai – Vietnam's Heart – Waylie Tran

13 Vietnamese Wedding Traditions and Customs