DD, you would probably be horrified by what passes for Tex Mex food in most of the world. I was in a supermarket yesterday and there was a big array of Mexican meal kits. These are basically a packet containing corn-based taco shells or flour tortillas or similar, along with a packet of sauce and some dry spice to add to some beef mince (I think you say chopped meat or ground beef instead of mince).
The weirdest place I've encountered a Mexican restaurant was in post-Communist Slovenia in 2001. It was one of a tiny handful of international style restaurants in the capital city. Their guacamole was awful, a watery green salsa that had never seen an avocado. Their "Mexican" beer was made in France and according to the label it contained tequila. I remember my New Yorker girlfriend at the time telling me that in Poland, where she lived previously, they called limes "capitalist lemons".
In parts of Sydney you can grow mangoes and bananas and the climate is almost subtropical. Where I live we have a weird microclimate so we get frosts in winter. That rules out a lot of tropical food crops. We also have awful soil that is basically rocks and sand, so growing stuff is difficult.
Well, you are probably right about my being appalled at some things that pass for good food over the globe.
Since you seem to know many of the differences, I appoint you as my Ambassador Of Culinary Delights to all points south of the Equator and I feel certain that you will continue to fight the good fight when it comes to specific cuisine styles.
Just a "heads up" from the resident horticulturist on board here; the way to make bad soil better is to add lots of organic matter to it, such as compost.
This, alone, will go a long way toward balancing the pH (near seven, if possible), maintaining steady moisture content, encouraging beneficial bacteria and fungi growths and help the soil become more tolerant of extremes in temperature, erosion pressures, even pest invasions.
Start small. Do a few herbs.
No need to do any soil testing to start out. You already know your soil is depleted. But like most depleted soils, it is likely to still be very fertile. It just needs a hand or two to make that fertility available to plants you CHOOSE to grow and get it back to being productive. Organic matter, balancing pH and pouring water on it all go a long way to making a garden possible.
Start small. Grow some cilantro, right now. You will have a flavor that can not be duplicated.
Plant some fresh garlic for (much) later. Yep, the garlic you buy in the stores will all grow. Just divide it into it cloves and plant away. Start them inside in small pots if you are unsure of viability of the plants.
BTW, never throw away the root part of an onion, when you are cooking. Almost every one of those little, often discarded root ends will grow a new onion.