Sr. "human" here.

If you always use your first output then you are not a senior engineer, either your problem space is THAT simple that you can fit all your context in your head at the same time first try, or quite frankly you just bodge things together in non-optimal way.

It always takes some tries at a problem to grasp edge cases and to easier visualize the problem space.

Depends on how you define "try". If someone asks me to do something I don't come back with a buggy piece of garbage and say "here, I'm done!", the first deliverable will be a valid one, or I'll say I need more to do it.