I'm also at a loss of what else to try. Since we cannot see what's going on inside it makes it hard to know for sure what it is. Lash material can vary in size and scope greatly, some birds entire oviduct is just filled with it and there is no way it can pass. It sometimes has egg material mixed in with it, like malformed shells. One of your original pictures made me suspicious that it might also be tissue, which is why I didn't suggest trying to remove it by pulling gently. I would not want to do more damage. If she were mine I think I might take a wait and see approach for a little longer, if she seems happy and comfortable, eating and drinking and pooping, in the hopes that it might pass. But if she starts to go down hill, then I would probably end it rather than let her suffer. If you decide to wait, I would still try to keep it moist. Below is a picture of the reproductive system, which may help, as you can see if the entire oviduct is filled with the material there is no way it can all be passed, and you can see where the shell gland is, which may be the issue as suggested.
View attachment 2117213