Oh I am so sorry that you are dealing with crop issues. It can be quite frustrating.
Did you discard the stool softener capsule and squeeze out the content and gave it to Lydia? I learned the hard way not to feed the whole capsule...
Did she have any egg laying issues? (underlying condition)
We have dealt with crop issues extensively at this point... DH and I have also read so many threads on crop issues. So many of them are like what you are experiencing: tried so many things including coconut oil, stool softener, acidified copper sulphate and no success. But one day all of a sudden, after so many weeks, the crop magically cleared... sometimes it coincides with right after deworming.
So I know how frustrated you are. Take a deep breath and be patient.
We have noticed they always really like watermelon with crop problems because they need a lot of liquid to flush out the crop. So it is important to keep Lydia hydrated. Perhaps offer her watermelon again.
I recommend you try slippery elm. Last summer our hen Light had a persistent case of impacted crop and we drove 2 hours to Raleigh hoping for a crop surgery. The vet did other things instead and prescribed a few things including slippery elm. She got better very soon after that. This summer she got impacted crop again (likely due to molting, her crop tends to slow during molt) and we just went to a co-op and bought slippery elm. And it worked again! Coincidentally, we dewormed the whole flock the day before we fed Light slippery elm so it could have been the dewormer (live roundworm was found in Light's poop.)
I wish you good luck and keep us posted. Make sure she is hydrated.
edited to add:
this is what we bought in a health food store locally. But any powder should do. I can specify the dosage if you decide to give it a try.