I was thinking about that question earlier, and my honest answer is that I usually handle it by giving myself a smaller starting point.
If I look at the whole task at once, I get stuck, so I pick one simple thing I can finish in a few minutes and let that create momentum.
That works better for me than waiting to feel completely ready.
I also try to keep the room quieter than usual, because any little distraction seems louder when I am already hesitating.
If I can, I write a short list on paper instead of on my phone so I do not slide into other apps.
It is not a perfect system, but it helps me move.
Most of the time, once I begin, the rest becomes much easier to imagine, and I am usually relieved that I stopped overthinking it.

I ended up trying that routine you mentioned, and it actually helped more than I expected.
I kept the morning very plain, did one thing at a time, and did not push myself to be unusually productive.
That was probably the biggest difference.
Instead of stacking too many plans together, I left a little room between them and stopped expecting every hour to be fully spoken for.
By the afternoon I felt steadier, and my mind was less cluttered.
I also noticed I am better at following through when I prepare small details the night before, because it removes that early indecision that can throw off everything else.
I may keep doing it this way for a while.
It feels simpler, and the whole day seems to move with less friction when I stop trying to optimize every minute.