I have Tacitus book, The Annals. I had been some months ago began to read it, he does describe the battle in the Teutoburg Forest. I was surprised at the shape of the Roman army from his descriptions. It was not the well equipped, beautifully outfitted army we all have been shown in many movies and books but sounded more like an army of tired poor shoddily dressed soldiers. Very much war weary. He described that Rome had a thing where one had to sign up for the army, had to put in something like 13 years of servitude, was not paid well, poorly fed and I think they had to buy their own outfits. It sounded just gruesome that battle. Those men fought with real courage in the view of the fact they were not properly equipped and there was a mutiny at one point.
Before the Marian Reforms (pre-Empire) they were citizen soldiers. They had to provide their own equipment. By this point they were very well trained and equipped. They were deceived and Arminius lured them right into the kill box. The Maniple system was designed for battle on an open field. They simply had no chance of surviving the trap. Part of my reason of posting this is so folks learn important lessons (politically) not to walk into a trap set by the enemy (See Jan 6th)
The Romans were heading for their winter quarters across the Rhine and were probably on their last legs after a summer's campaigning and occupation duty among the "savages". The Germanic tribesmen were even less well equipped. But it was their forest and they were led by a trusted auxiliary officer with long experience serving in the Roman army. He knew its every strength and weakness and took full advantage. The "battle" lasted three days with the legions being slaughtered piecemeal. No set piece battle, just a long dark forest nightmare for the exhausted and confused Romans.
Varus (who had been warned of Arminius plans beforehand but didn't believe it) committed suicide before he could be captured, tortured, and sacrificed. His tribunes and centurions weren't so lucky.