I often tell the story of Tom Wolfe and "Bonfire of the Vanities". He began the novel when he was already a famous celebrated writer (who I already idolized at the time). He went to Jann Wenner and asked him if he could get a serialization deal in "Rolling Stone" magazine. Wenner laughed. He couldn't believe Wolfe would want to stoop so low.
Wolfe said if he wasn't forced to deliver a chapter every month he'd never get the novel done. So that's how it happened. Once that first chapter was published Wolfe faced certain humiliation if he didn't finish it.
I tell myself, if Wolfe had to resort to mental tricks to get things finished what does that say for the rest of us? It gives me comfort. As you say, and all writers know "writers write".
You get there anyway you can, no matter what you have to do. I know I go through some humiliating tricks (and I'm just part-time). I'm sure you do too.