A narrated account will be compared to the forensic evidence. If they differ in any way, or there is a judgement call as to what may or may not have happened based on the evidence, the evidence will win and it will impeach your recording.
What needs to be on the recording is that there’s an intruder, that you’ve dialed 911, that the police are on their way, and ‘don’t make me shoot you, I have a gun’. If you shoot them, and you are a trained first responder or have a current CPR card, and you are sure they are dead, then begin efforts at resuscitation.
If they prosecute you, then they will ask why a trained first responder failed to try and administer first aid after the danger had clearly passed (’after the danger passed’ is a judgement by the prosecutor after the fact that may or may not work with the jury).
I work with corrections officers that travel everywhere with a concealed weapon. They are EVER vigilant when off duty. They will come after you professionally in a DGU case even if the shooting was righteous by showing that you failed to provide first aid after the fact.
If you don’t have the luxury of 911, and you’ve already shot them, say as little as possible.
When the perp goes down, I'm going to stay behind cover and not take a chance that he's faking in order to lure me within reach. Let the armed responders deal with him.