I personally (as a non-straight person) wouldn't mind a lgbt character dying as long as it actually contributed to the plot. The point where most people get annoyed is when the death is just for emotional response or to further the character arcs of cis and/or straight characters (basically when minority characters are treated as more expendable than others).
If it's absolutely necessary to further the plot then it's understandable, but be v e r y careful about killing off a character for the main purpose of helping another's character arc, especially with minorities and especially if it's the only aspec or nb rep you have. If it's possible to rework the story so the death doesn't happen, I would advise you to do so (and if not, try not to let them be the only aspec or nb character you have).
They're being killed off because my MC (Zenith) needs to understand what it feels like to lose someone close to you, and so he'll stop brutally murdering people without a second thought (that part may take awhile, but the death will get it started). Jayden may be my only nb person I have, but I do have a lesbian couple, a gay love interest, and a pan-romantic asexual main character.
I don't think it'd be possible to re-work the plot to that extent, its a pretty key point for Zenith.