That's as much as I know. I've just tested DejaVuSerif fonts on my Kindle in Koreader and they work on my side.
Fonts from:
https://github.com/dejavu-fonts/deja...g/version_2_37
I installed all Serif fonts into DejaVuSerif directory in Koreader Fonts folder. Both DejaVuSerif and DejaVuSerif Condensed show up in Koreader, and they work when selected.
Kindle Scribe gen1
KoReader v2024.11-267-g29908800b_2025-03-25
Internal Storage/Fonts (no fonts here)
Internal Storage/Koreader/Fonts/DejaVuSerif/ (all DejaVuSerif fonts here)