Running on empty and well and truly stuck in the main things (my fault for working two things too similar to one another yet also quite different – but not different enough, apparently) so I'm making an attempt to bring back The Etudes, with specific rules sourced from other, earlier attempts at an "unsticking" exercise: 50-100 word fictions, written and published in two days (Mon/Tue or Thu/Fri)... and that's all I've got. Will probably add more specific rules to each individual piece to meet the moment of the required unsticking. Thinking of this, from Rick Rubin's THE CREATIVE ACT:

"There are no bad rules or good rules. Only rules that fit the situation and serve the art, or those that don't. if the goal is to create the most beautiful work possible, then whatever directives are truly in service to that end are the right ones to use... they can challenge you to become better, to innovate, and to bring out a new side of yourself or your work."
Rick Rubin https://www.worldcat.org/title/1313903954

This being the theory.