I drowned and was resucitated when I was a kid. I remember peace before blackness. My first breath after CPR was the most painful one of my life. This happened when I was 5, I still remember it and it is still my most painful breath ever. After that I puked water and felt like shit for 2 days.
My grandmother died on the operation table while they were trying to get to her gallblader (same issue I'm having, how ironic) back in the... 50's I want to say. My mother wasn't born yet. Anyway everytime she would tell us that story, she said she felt no pain, it was bright and music was playing. A voice told her she wasn't done yet and she woke up after the surgery to a bunch of doctor wanting to check if she had brain damage and all.
So I grew up thinking death is nice and you're at peace. My whole family talks openly about death (but not suicide ofc) and it's not something I'm scared of. It's natural, we all die.
I just wish we could have a better say as to how and when.