I'll offer a middle ground that requires a lot of polishing as I go.
I write polished and readable story as I go. The only thing I would say is 'first-draft' is that I may postpone easy details that don't influence the character or plot but may add authenticity for the reader. The name of a piece of equipment that I know exists; for example do doctors use a special name for the light in the operating room, or just call it the light? What is airline pilot terminology for reversing course? Details like that can be left out of the first draft; the particular name of a fatal cancer, the types of trees native to Oregon or Texas, whatever.
For prose I focus on character speech and attitude, emotions and thinking, and I am just not happy with broad strokes. I need to see their interactions develop sentence by sentence and make sense and work smoothly in polished form.
As an author I cannot write [they fight and make up] and move on to another scene; to me the exact content of the fight, the exact way it starts and ends, changes my characters! Just as it changes us all in real life. There are things we say that cannot be taken back or forgotten or forgiven.
Saying [fight and make up] means later I must devise an interesting fight between lovers that has NO ramifications on them later in the story. That feels like leaving the hard part for later, and in my view that is NEVER a good idea.
Consider the ramifications: If I do all the easy parts of the story first, all I have left is the hard parts. Then what? Do the easiest of the hard parts? Then I am left with increasingly harder parts to finish, and the result is: the story becomes impossible to finish, there is no way to accomplish what must be done and retain the plot.
Do the hard parts as they come. They develop and add nuance to your characters. If you have a plot plan and character arcs, that is fine, but revisit it often. Did the scenes you just wrote make that plot less plausible? Is some future duty of a character now implausible? If Alice and Bentley are enemies that become lovers later, did you just make that almost impossible?
Every scene transforms something in characters, even if it is subtle. Bentley the detective suspects Alice of brutal murder (oh, she is guilty!) but while spying on her, sees Alice secretly helping prostitutes. For what nefarious purpose? None he can find, Alice is truly being an altruist, and fearless, and trying to make lives better and relieve hardship. Bentley is being changed, and in the reader's eyes, Alice is being revealed.
Write the way you write. My advice, from experience, is get used to the idea that half the prose you polished may have to be revised and re-polished, or even scrapped. Don't get emotionally attached to it, if you wrote something awesome once, you can write something awesome again. Don't try to change your way of telling good stories to be more efficient.
Also, don't put off the hard parts for later! It is better to finish a story with a lot of easy work left to do, than it is to work for ten months and have nothing but intractably difficult plot and character transitions left to do, scenes that won't exactly fit with what comes later, or create incongruities, and a lot of them pile up and make the story seem forced.