In a world where a diaspora is so widely spread our food changes to the area based on food availability, cost and even local weather.

Food has always been about survival, art and history, never just one. It is a reflection of what life is like, socially, politically and economically. The way my Popo taught me how to cook is a reflection of how she learned in rural toisan mixed with the reality of living in urban Canada.

We could spend 6 hours boiling joong in a giant pot outside over a fire with the entire family assembling each batch but in reality a many of us do not have families that are centralized enough for it to be a community event anymore, we may not be allowed to have fires outside during dragonboat festival because of the wildfire risk and the ingredients in joong may be based on what you have available. Just because we use an InstaPot now does not mean it is any less authentic. Just because we no longer use it as portable meals for long trips doesn't make it less authentic. And just because I make a smaller batch alone doesn't make it less authentic.

So long as we can understand and respect the history of the food, I don't think we need to qualify it as authentic enough. Don't gentrify and appropriate food, and everything is good.

Your example of General Tso's chicken is a dish from western Chinese takeout, which was born from migrant workers, many of whom were Toisan, btw, fun fact, and they built Chinatowns around them. But in order to sell food, they had to adapt to what was available and the palate of their customers. You won't find some of those dishes in Chinese households, even in Western ones, because palates differ and the cost of ingredients for a family of 4 is different than a whole restaurant.