If one called Trung Luoyue you'd 99.99% of people, including those that grew up in Vietnam, not recognize it at all. And I'd expect the general goal is to have people recognize things in the game, so saying "Vietnam" seems like a find compromise to reach that goal
I mean the name is kinda funky but yeah by Civ conventions it's always going to be Vietnam and nothing else.
However, she'd follow the precedent set by Ba Trieu. Palatable to the uninvolved, but wildly standing out in a historical game if you are familiar with the clothes, the artifacts and the history in question. Thus my preference to pick someone else.
It's basically "France (Vietnam), lead by Vercingetorix (Ba Trieu/Trung), wearing a tuxedo (ao dai) and a tophat (the Nguyen turban) holding a bronze antenna(e) (Dong Son) sword." They could always top it off by adding an elephant riding element to her so we'd have this Vercingetorix sit on a cataphract-equipped warhorse.
Fine for Rise of Kingdoms but strongly out of place with the rest of Civ leaders.
How is Le Loi not Vietnamese?
The historical Vietnamese were in an antagonistic/foreign relationship with Thanh Hoa people, his birthplace.
The records about him were fairly unanimous about portraying him as an outside force that walked into civilisation proper.
His original rebellion resulted in him being content with an agreement which gave him land in the mountains. And he had to be convinced to lead another rebellion by an official from would-be Hanoi looking for military assistance.
Mountains being the land of the barbarians that no historical Vietnamese would willingly live in.
After his successful campaign against the Ming, you get a Mac state which is literally built on the idea of certain Vietnamese families fleeing from what they saw as foreign rule. Similarly, many of his exploits afterwards are about pacification of the locals... he wasn't a liberator as you'd hear in a tourist guidebook, he was another conqueror.
Finally IIRC his grave goods were consistent with a Muong grave, not one of a Kinh (i.e. modern Vietnamese). Which is pretty damning considering this is an emperor we're talking about.
Does this disqualify him from modern Vietnamese history? No.
But since Vietnamese history is just a void for most of people playing this game, I would really prefer if Firaxis tried to tackle the topic with the care used in any modern historic research. We don't dress Qin in Peking opera clothes because we know better, Roman buildings are painted as they should be, etc.
Hence if I had a choice, I would 100% pick a valid, unquestionably Vietnamese emperor known for a golden age and having a large part in shaping modern Vietnam (being the guy who conquered Champa and opened up the south).
Rather than a person whose life and story is a tool used to push certain narratives. Part of the narrative is relatively harmless since the Vietnamese crushed the last hopes of the culture standing on its own during the last century (tellingly, both the French and Americans used the "Montagnard" people against them), kind of in line with calling Ryukyuans Japanese, their language a dialect and their religion Shinto... at the end of the day it is now almost really true.
But tit's used to push narratives that both distort understanding of Vietnamese history (from a multifaceted state of nations with their own cultures and agendas into a modern Kinh nationstate) and argue for unanimous hatred of the Chinese (it's never "so and so event lead to an invasion" "so and so people abused the locals and the authorities were either unable to respond to it or complicit because they got something out of it"... It's always all of China out to enslave every single man, woman and child for the sheer and pure joy of causing suffering).
And support of these modern narratives is definitely against what historical academia stands for and I'd hope Firaxis as well.