Yes, the word "peaceful" is probably a relative term. I would like to go out as peacefully, calmly, and rationally, as I can. But again, that's probably all relative. And as the person above states, even people who die of natural causes don't exactly go out peacefully. I'm not sure there is a way to have a 100% peaceful death.
I think the main difference is when someone dies a natural death, they're usually in a hospital or in hospice where they're given medicine so that the family doesn't see what they're actually going through. Or if the person dies naturally "in their sleep", everyone else is asleep at the time too, so no one actually sees what they go through.
I'm expecting some pain, some anxiety, and all that kind of stuff. I'm just hoping to mitigate as much of it as I possibly can and be as calm as I possibly can. Some of it will be mitigated through medication. Some of it I'm just going to try to do deep breathing and try to focus on happy thoughts or being released from my body or whatever other thing I can think of that might make me calm. Maybe listen to calming music or something.
I am under no illusion though that it's going to be what people would classically define as "peaceful" likely.
Then again, who knows, we all may be pleasantly surprised. Maybe our brains will be flooded with endorphins when the time comes and we won't even get to know what's happening. That would be the best outcome.
Unfortunately, I don't think that phase happens until right before the very end. It's the rest of it that's going to be difficult.