Writing, especially writing a novel or other longer work, is an uneven process. There are days where you cannot type fast enough and fear to stop. The well of inspiration brims over and ideas take shape before your eyes. It's almost miraculous, and deadly addictive.
Other days, most days for many of us, are more of a grind. We know what we want to write, but our prose is dull, repetitive, unsatisfying. The well is tapped out and all we can do is try to move forward until it refills.
And then. And then there is the dreaded writer's block. Not only is the well empty, but the mere thought of trying to put pen to paper - physically or virtually - is impossible. Sometimes this lasts only a day. Sometimes it drags out for longer, weeks or more. The suffering is real.
I haven't been blocked recently (Fate, please ignore that temptation) but I've definitely been grinding for about a month. I know I can return to bland passages and scenes later, but I've grown worried about the run-in to my finale, and even the finale itself. Does it make sense? Are there enough obstacles? Is the conclusion satisfying? Kinda, no, and not really. So, grind it out and hope for inspiration to strike.
The breakthrough, when it came, wasn't a thunderbolt. It was lots of little things that popped into my brain at random times - usually when I was far from a keyboard or even my phone - and slowly accreted into something more than their whole. It's still a little rough and ready, but I think it works and I think the finale, especially, is far more satisfying. Oddly, the core inspiration was a comment made by one of my Book 1 beta readers about where they expected that book to go. It was a great idea, just one book too early!
Of course, the "break" part of "breakthrough" means there is damage. Two long-planned scenes will have to be cut, or at least moved to the final book in the series in a different form. I was looking forward to writing them too. But one of those core pieces of writing advice is "Kill your darlings!" Sorry, darlings.