Honestly the amount of crazy code involved in Linux font rendering[1], and then you get to CJKV support[2], it's mind-boggling. Even then, it's nowhere near as good as macOS :-/

[1] https://gitlab.gnome.org/GNOME/pango & https://github.com/harfbuzz/harfbuzz

[2] https://www.amazon.co.uk/CJKV-Information-Processing-Ken-Lun...