First time making quark and also first time trying to do anything outside of Greek yoghurt (apart from homebrew alcohol).
I know its only kinda cheese but it turned out whey better (heh) than I expected. Really tasty! It's not really a thing in the shops here in Australia.

Good job. It isn't "kinda cheese", though. It is real cheese. It's a low fat, drained lactic cheese.
There are 2 main categories of cheese: those with acid coagulated curds and those with rennet coagulated curds. The curds are chemically different between those kinds of cheese and they make very different cheese. Within the acid coagulated category, there are also basically 2 sub-categories: direct set curds and lactic set curds. Basically you can just pour acid (any acid, even lactic acid) into milk and it will curdle the milk. Or you can add lactic acid bacteria to the milk and let the bacteria produce the acid for you. They always produce lactic acid and this is why we call these "lactic set curds". Maybe we could have a better name :-)
Notic that your Greek yogurt are "lactic set curds". Yogurt is just an undrained lactic cheese. If you drain it, you get a drained lactic cheese. It might surprise you that there are many famous traditional drained lactic cheeses, though usually they are aged with mold or yeast on the outside to make the cheeses go soft over time.
Using yogurt bacteria to set the curds is actually a bit unusual. Skyr does that. Normally you would use bacteria that prefers room temperatures. A good example is cultured buttermilk or sour cream. You can make a "yogurt" exactly the same way that you use greek style yogurt, but you start with a culture buttermilk or cultured sour cream and you leave it at room temperature -- you don't heat the milk (or at least not much, if you do at all). This gives you a different flavor and potentially slightly different texture.
Usually quark uses those room temperature bacteria and usually quark is made with skimmed milk.
There are lots of super nice lactic cheeses. I often make them because they are really low effort (and I'm lazy). But also they are really delicious. Aging them can be tricky, but once you learn how to do it, it can make the cheese even better over time.
Edit: I should point out that using yogurt bacteria for making cheese is not unusual. It's just not that usual for making lactic set cheeses. A good example of rennet set cheese that uses yogurt bacteria is Parmesan.
Thank you so much for all the info! This was made with whole milk and buttermilk for cultures :)
Ive also aged meats before so I think I'll have a bit of learning curve but have some of the basics for that at least. Could be a year of cheese making in my future haha
Most bacteria acid sets cheese also use very small amount of rennet: cottage cheese, formage blanc, etc
Looks good Thanks for all the information