I wonder if there might be a way to create "trigger warnings" for those who desire them without spoiling chapters for everyone else? Perhaps some kind of link only saying "Trigger Warning, click for details"? Even this is somewhat of a spoiler, especially if the event was supposed to be a complete surprise in the middle of a peaceful scene (as you'd be forewarned that something "triggering" will happen) but it's better than a straight up spoiler with specific references to as yet unread chapter events.
Personally, I consider translator-inserted "trigger warnings" to be rude to the author and the readers as they interfere with the way the author intended the reader to experience the flow of the story, and they even act as spoilers. I don't want to argue the ethics or merits/demerits of inserting trigger warnings into the work of authors who didn't put any in themselves, but I would like to point out that it comes at a cost to all readers. If they somehow "must" be put in, then I would hope the cost to all readers is at least considered and minimized.
This said, I'm only speaking from the sidelines here. I want to give a sincere thanks to those who are putting in all the effort to provide these translations. I'm enjoying reading this and appreciate your work.