@thirstybear Detailed todo list (ranked by priority) with very concrete/boring items.
Step 1: make a detailed list (don't worry, brain, you won't actually have to *do* any of these things)
Step 2: first item on the list Is My Whole World. There Is Nothing But That Item. Mindlessly Execute.
Step 3: check off the first item, drink water, goto step 2
The trick is to make the items take no creativity. It's not "make car appointment", it's "call the mechanic and schedule a time". -- no wait, I'm stressed about my schedule --- actually, it's "review schedule and make sure it's up to date" followed by "while looking at the up to date calendar, call the mechanic and schedule a time". They have to be linear tasks or I'll quit. The task-making process feels like coding.
Or, if that process isn't enough, then I add in music with a really high tempo, preferably stuff I listened to as a teenager so there's a slight nostalgia dopamine hit to supplement the music-induced heart-rate increase.