Replace blue loading line while loading api

hello everyone, I’m french so excuse me for the translation

i would like to modify the blue progress bar during a flow or workflow work

i already know how to replace the blue bar with something else while the page is loading

i also know how to make the blue bar invisible by adjusting its opacity in the settings

but during the workflow work, I can’t do it.

for example I generate in image thanks to openai, and during the generation which is long, I would like to put a spiner or other in its place, but the condition “page loaded entirely” “yes or no” does not work in this case.

you have to wait until the image url is generated by openai without animation and this is very long !!

for this reason I would like to find a solution to my problem

thank you in advance for your answers