When I first read about Mesopotamia, I thought there must be some “lost” ancient civilizations as all of that couldn't just happen out of nothing. Now, with Göbekli Tepe and similar sites, we start to put the puzzles together and there's no Atlantis in it. It turns out that humans at the hunter-gatherer stage, could develop and pass on more knowledge than we previously thought.
Yes there were a few remaining pockets of Aurochs, but most were gone. Same for the Giant sloth.
I notice you used these two examples to invalidate the whole argument I made without mentioning all the other animals that did go extinct - nice try.
As for a previous civilization(s) - you are rapidly becoming in the minority on that point of view with the constant barrage of new information about the past - both from discoveries and from the use of modern tech cf satellites and LIDAR.
Clinging to the meme of humans did it (killed off the mammoths) has now become so unlikely that hanging on to that POV is silly.
Using GT as an example that there was no previous civilization belies the fact that we sill have no idea who built it, why and how - if ‘they’ were the stereotypical image of ‘hunter-gatherers’. Using the lame explanation of they ‘could develop and pass on more knowledge than we previously thought” exposes the standard consensus thinking - the bane of any advancement in any field.
If you want references there are hoist of them on the internet, in libraries and books in print. Ask them, not me. I’m dome here.