Lots of things I think, lack of understanding, lack of motivation. Typical suspects. I think We look for easy solutions like using LLMs for instance (but not exclusively) doing busywork when we shouldn’t be doing the busywork in the first place. Busywork is just example, but in creative non-busywork it could also be the extensive, time intensive exploration required to advance. In jazz for instance spending hundreds if not thousands of hours on scales and arpeggios over the instrument is a non-negotiable expense to access fluidity.

So while I think LLMs are great fun and I don’t judge anyone using them, personally wanting to use one for a difficult problem is a flag that I should allow more time to think before going ahead.

Not OP, but much writing advice with which I'm familiar, and my own experience, both suggest these are symptoms of an error made earlier and not yet recognized.

If I can't figure out where the plot could possibly go from here, go back and look for where I sent it off the rails earlier such that there's nowhere to take it now; if I can't find dialogue or action that fits, go back and find where I put the character in a situation they'd never get themselves in, or miswrote them to respond to it in a way they never would. Stuff like that, especially once it's had you stuck too long for inspiration latency still to be tenable as the cause.

Writer's traffic congestion