The series was lost after the first ball of the first test.
At least psychologically.
I’m sure Root/Silverwood chose to bat on a greentop at Brisbane to make a statement* (that couldn’t be backed up with action) although what they were saying was basically we don’t know what we’re doing.
* reference to Nasser Hussain when he won the toss on a belter of a wicket and put the Aussues in, and they scored 492, eventually winning by 384 runs.
And then Steve Harmison, bowling the first ball of the 2006/07 Ashes series, which went straight to Flintoff at 2nd slip.
England are NOT mentally tough enough.