This is probably the best approach, but I don't think there is an specific technical solution, it depends on the situation. Emojis and icons are easy, just a icon set like you said, but I'd like to see some examples, probably some of them are not that easy as change icon theme.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
Probably creating/using a specific icon set just for dark themes. I'm sure there are icon sets out there already that keep that restriction in mind.
Are you able to target emojis with css to replace them with an icon?
Someone on Twitter had some input on this:
This is probably the best approach, but I don't think there is an specific technical solution, it depends on the situation. Emojis and icons are easy, just a icon set like you said, but I'd like to see some examples, probably some of them are not that easy as change icon theme.