On my screen, the final image flickers at a high rate.

WCAG 2.1, Success Criterion 2.3.1 Three Flashes or Below Threshold (Level A) says (as I'm sure you know):

"Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds."

https://www.w3.org/TR/WCAG21/#three-flashes-or-below-threshold