The Didache is not inspired. I translated it in 2nd year Biblical Greek. Some things directly quote the Bible, others paraphrase, as this does in many places, and other things are not Biblical.
The passages we did in my class, had an interesting part about evangelists. They were not supposed to stay in town for more than 3 days, not be given a bed or food. Too bad the prosperity preachers don't have to obey that! Lol
However, you are right about it showing something similar to what the Bible says. But, no date given for when the return could come, although a sense of urgency. When people in the 1st or 2nd century AD get urgent about the Second Coming, that sure points to how wrong they were, doesn't it?