Even once selected for Delta troops start all over with basic marksmanship and dry fire for like a week before one round goes down range.I go back and forth that. I agree with you to a degree. Bullseye shooting is not realistic for self-defense.
But if you aren't having a tight group in a controlled environment; flat range, reasonable distance, no distractions, no stress, no one shooting at you, etc.... you're probably not going to be accurate at all in a self-defense situation.
A "combat accurate" grouping on a flat range quickly turns to spray and pray in an "oh crap" situation
You need to have the fundamentals down. And shooting B8’s for accuracy are a needed skill.
As far as other factors like drawing moving placing good hits besides classes from relevant instructors shoot some IDPA or USPSA matches.
Don’t worry about winning just shoot. It’s a good and reasonable venue (they are generally somewhere close any given weekend and cost 20 bucks and 100-200 rounds. You get to draw shoot, move have no shoots to factor in.
So that and shoot the drills I posted or others weekly and you will see improvement