When one is doing anything, the activity of teh brain's default mode network reduces.

However, when one "does" TM, this is not the case. Note the quotation marks around "does."

TM isn't focused attention. Despite your claim about returning attention to it. In fact, attempting to put into words what happens during TM is detrimental to the process.

What makes TM special is that it isn't special. It is merely normal thinking that somehow, kinda sorta involves something that kinda sorta can be called a mantra (if you squint your eyes really hard)... kinda sorta.

As Maharishi Mahesh Yogi explained to someone: I have taught you nothing: https://www.youtube.com/watch?v=9L_L5dIwc00