That’s the wrong question, but I do have some answers
I've always hated the deadlocked advice some authors give: apply ass to chair, stare at blank page, and sit until you've reached your daily word or time limit. Sure, eventually some word salad might come out this way. But for me, the cause of "writer's block" is almost always that I simply haven't thought about a story long enough or that I'm approaching it from the wrong angle. Once I cracked these two codes, I can write a pretty reasonable long-form draft in one or two well-caffeinated four-hour sessions. So yes, I totally agree that time spent writing is the wrong metric. The real question should be something like, "How should you prepare your writing time?" And the answer to this -- at least for me -- is: generate idea, step away, take notes, think about them while running errands, write. If necessary, rinse and repeat.