I don't have much, but probably one of the more interesting peeks behind the curtain was an afterword I read in The Eminence in Shadow Volume 4. For context, TEIS started as a webnovel and the first 3 LNs were basically just compiled WN chapters, with slight editing. LN4 however, went off on a completely different direction and the original WN story was abandoned (a reference to it would later show up as an easter egg in the anime).
In the afterword for LN4, the author apologized for the long gap after LN3 since they were suffering writer's block while adjusting to writing a LN-original plot. They then wrote a bit about how different it was to write for a LN vs. a WN. I have transcribed the relevant paragraphs below:
I've been doing the whole web novel thing more or less since I started writing, and over time, my writing style has gradually shifted to one that's more suited to that format. In other words, I would regularly check in with the readers and make edits and sometimes rework entire plotlines based on their feedback. Even if their opinions differ from mine, if enough of them are in agreement, I feel like the right thing to do is to respect how they feel. To this day, I still believe that, and I make a point of only doing things "my way" in the course of moving the story along the way the readers want. That's the writing style my web novel days have fostered in me.
However, that gave me problems when I decided to have Volume 4 go off in its own direction. Without the ability to post a chapter at a time and make changes by looking at the readers' reactions, I found myself at a loss for how to proceed. I would write a little, then end up deleting it all and starting over from scratch. That went on for over a year.
In the past, my stories weren't something I wrote on my own. They were something I built together with my readers.
I hadn't thought before about how different it must be to write for these two formats, so I appreciated the author's candor when it came to his difficulties adjusting. He might still be struggling to this day as LN7 has yet to even be announced, despite LN6 releasing back in October 2023.