There is no consensus. Most secular and apocalytpic scholars believe Jesus is here referring to the end of the world within the next 40 years. Some Christians scholars say that Jesus is referring to the imminent fulfillment of some of Mark 13 but not all of Mark 13 (that the Temple will be destroyed within 40 years but that the Son of Man will come in the indefinite future). This reading drives an artificial division within the discourse.
What we should conclude is that Mark 13, and most of Jesus' teachings about the coming judgement, refer to the fall of Jerusalem in AD 70. Just as Jeremiah used the Valley of Gihinom in reference to the coming Babylonian crisis, so did Jesus use the same valley (Gehenna) to refer to the coming Roman crisis.
Ancient giant. He was one of the rephaim I believe, or maybe one of the other nephilim tribes (I cant remember which but I know it is mentioned in the biblical passage where the Israelites defeats him). This book The Giant Cities of Bashan: And Syria's Holy Places details a relatively recent (last 100-200 years) archeological expedition that went to these giant cities where they found some of the remains of their basalt cities. It is fascinating.
If by "believing commentary" you mean written by a professing Christian, look no further than Walton.
https://www.amazon.com.au/Genesis-Application-Commentary-John-Walton-ebook/dp/B004FPZ29A
You might not agree with his views on Genesis 1-11 though, but his scholarship is top notch.
I prefer the idea that we are missing an original beginning as well as an original ending, as argued by N. Clayton Croy in The Mutilation of Mark’s Gospel (Abingdon Press, 2003). If I recall correctly, one of his suggestions is that the original, or an early copy, was a codex not a scroll and that the outermost sheet somehow came off and was lost.
Amazon description:
“This book theorizes that there was probably more to both the beginning and the ending of Mark's Gospel than we currently have in our Bible. It was once the consensus of scholars that Mark lacked its ending. Croy asks why scholarly opinions changed on this question during the late 20th century and whether earlier scholars may in fact have been correct. In short, this book has the potential to re-open a major debate in Markan studies. Beyond scholarly interest in the original extent of the Gospel text, there are implications for our understanding of Markan theology. If a conclusion has been lost, Mark may not be as negative in his portrayal of the disciples as we now assume. The credibility of the disciples - and Jesus’ own credibility - also may have been rehabilitated by the original ending. Croy urges that we should not assume that post-resurrection“ appearance stories were unimportant to Mark or that Mark’s theology of suffering would be incompatible with a triumphant outcome. The challenge to the scholarly consensus will be of interest to academics; the theological implications will make the book useful in seminary classes on the Gospels. The author’s demonstration of the connection between the social context of biblical research and our ways of reading the Gospel is important for theological education in general. Readers will also benefit from an awareness of the process by which we have received the texts printed in our Bibles.”