Where are my manners,while this forum has its fair share of vitriolic nationalists/irredentists there's still some reasonable members,but welcome to this forum.
Uncorroborated sources/mythology don't fly in the academic community,therefore they shouldn't be used as a legitimate substitute for primary/secondary sources.
While it is possible that individuals rooted in mythology might represent a set of ideals or a tribe or that some sort of conflict emerged between several parties however they are heavily embellished and contain anachronistic terminology.
That's the issue you can't attach prehistoric cultures to a later day fabrication,Chinese historians use the Erlitou culture as "proof" for the Xia dynasty however there's no evidence of writing therefore its not recognized by Western historians.
The same reason why the Shang dynasty was put under heavy scrutiny until oracle bones were found to record Shang era events and Shang imperial lineage.
Qin Shihuang's book burning have nothing to do with Van Lang/Hong Bang they were too distant to know of each other,neither did the Spring Autumn/Warring States maintain close contacts with Central Asians.
Hong Bang dynasty is a complete sham made by Vietnamese to prove that they are an older civilization and origin of Chinese culture.
1.Material culture is not indicative of suzerainty ie Dong Son bronze drums spread throughout parts of southern China as well as southeast Asia however there existed an independent tradition in Shizaishan. Many foreign cultures adopted Chinese culture and imported Chinese swords,mirrors as well as bells however this doesn't make them Chinese.
2.Chinese terminology as well as mimicry ie the terminology of Phong Chau is erroneous as it couldn't possibly have existed until the Sui-Tang era where 州 was redefined,as well as this famous passage:
東夾南海,西抵巴蜀,北至洞庭湖,南至狐猻精國(今占城是也)。
To the East it bordered the Southern sea,the west BaShu to the North Dong Ting Lake and to the South Hu Sun(Champa).
Is just ripping off the Huayang Guozhi.
3.The lack of Chinese sources indicating a powerful kingdom to the south or archaeological evidence of a bureaucracy that ruled southern China from Vietnam,writing etc.
4.Linguistics:Southern China had Austronesians,Tai Kadai,Austro Asiatics,Tibeto Burmans as well as Miao Yao speakers how can they all be Vietnamese?
5.No other ethnicity has myths of Hung Kings,a powerful country would surely leave behind descendants all over Southern China.
This is just the tip of the iceberg there are plenty of other evidence that contradicts the medieval Vietnamese narrative.
The issue is that Dong Son culture faded away after Chinese culture supplanted it and that it barely influenced other cultures,the bronze drums which the Vietnamese hold great pride over today were viewed as relics of barbarians by medieval Vietnamese.
Chinese legacy is widespread despite how Vietnamese want to deny it today ie historically Vietnamese surnames,architecture,bureaucracy,philosophy,linguistics,clothing,script were all heavily influenced by Chinese cultures.
Vietnamese claiming that they had a civilization that matched the Chinese in influence and territory is ridiculous,it would be like saying the Germanic tribes the Romans faced were the origins of the of the Romans.
There's no such as true Han Chinese,tell me are Northern,Central or Southern Vietnamese more Kinh?
Considering how you and your countrymen spew so many lies its only natural that Chinese would feel offended.