Although not something you would need to do in a research paper, this would be useful in other contexts (e.g., a TODO TeXmacs document).
You should check if a font has it. Then use the unicode code to get them into the document. I’m not sure how they work usually.
Emoji only seems to work for a few icons. When pasting “🖛” into TeXmacs, only “” shows up, the others are shown as unicode. I’ve tried different fonts and verified that they support all of these icons in LibreOffice.