Most readers will, at some time, have been reduced to tears when a character that has involved them deeply is killed off by the author. My first experience of this was at age 12 in the final chapter of the Lord of the Rings, when Bilbo departs for the Grey Havens. Since then there have been many occasions where I have stopped reading as the page blurs beyond my tears. Most recently this occurred in the last book of Ryan Sylander's Hook. Pick and Lens trilogy - if you haven't read this, please treat yourself by picking up the books (they are on Bookapy). They contain great writing, particularly the final of the trilogy, Shutter Release. Ryan writes of deep emotions with subtlety and aching beauty.
As a new author, I recently found myself at the other end of the pen, so to speak. Through my Eyes. Again. grew organically from the initial scene. There was no plot line and the interactions between the characters drove the first half or more of the book as Will, Col, Frida (Col's mother) and their friend, Lili, interacted with each other and the circumstances they found themselves in. As the story grew, I found myself looking at the far horizon where various endings flickered in the distant mists. I toyed with several (including one where Col and Mutti Frida were actually 'sleepers' planted by the KGB - but I could not see that fitting their characters and it was quickly discarded). Finally, I came to the ending that occurred in chapter 20 - and found that to get there in a believable fashion, I needed to kill a character.
As an author, I invest emotionally in my characters - even the ones I don't like very much - and so killing one of them is not easy. I struggled to find a way of reaching the desired ending in some other way, but none of the ideas 'fitted'.
In other news, the first draft of chapter 4 of Through different Eyes - the sequel to TMEA - has been posted to my Patreon - there's a link to this and my Discord server in my profile.