Ditto to the needing to multi-task thing.
I’m a writer for a living, and the mind-blanking thing is a hardcore reality.
I’ve developed something of what I call a “priming the pump” routine.
If there’s a certain topic I need to write about, I’ll toss on a podcast or some other sort of related audio in my earbuds and go for a walk (or do the dishes–something mundane that keeps my body somewhat busy but allows my mind to wander).
Once my brain grasps onto something from the audio, I’ll start an audio note in Evernote and just jumble out my thoughts that way…writer’s block is easy to get, but talker’s block, c’mon now?
Then I go back through and pull the parts out of my own audio file that becomes threads for my outline. Usually, by this point I’ve got enough threads together that I can keep going with the piece I’m writing.
The great thing about this is that the original podcast or whatever I’m listening to, doesn’t have to be right on topic, just topic adjacent. If I know what I need to write about, and I can get out of my own ahead to not be in the way, my brain will start making the connections on its own. Then it’s just a game of having a way to catch those thoughts and filter them once they’re not stuck rattling around my brain anymore.