Edit your ~/.config/fontconfig/fonts.conf
(if it doesn’t exist, create it), to something like:
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<alias>
<family>sans-serif</family>
<prefer>
<family>Noto Sans</family>
<family>Noto Color Emoji</family>
<family>Noto Emoji</family>
</prefer>
</alias>
<alias>
<family>serif</family>
<prefer>
<family>Noto Serif</family>
<family>Noto Color Emoji</family>
<family>Noto Emoji</family>
</prefer>
</alias>
<alias>
<family>monospace</family>
<prefer>
<family>Noto Mono</family>
<family>Noto Color Emoji</family>
<family>Noto Emoji</family>
</prefer>
</alias>
</fontconfig>