Hmmm, try:
<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
<alias>
<family>monospace</family>
<prefer>
<family>Fira Code</family>
<!-- Your preferred monospace font -->
<family>Noto Color Emoji</family>
<!-- Your preferred emoji font -->
</prefer>
</alias>
<dir>~/.fonts</dir>
</fontconfig>
Save as ~/.config/fontconfig/fonts.conf
This is what I have installed:
27 aur/ttf-twemoji 14.0.2-2 (+65 3.12) (Installed: 14.0.2-3)
21 archlinuxcn/ttf-twemoji 14.0.2-3 (2.6 MiB 3.2 MiB) (Installed)
17 chaotic-aur/ttf-twemoji 14.0.2-2 (2.7 MiB 3.2 MiB) (Installed: 14.0.2-3)
14 extra/unicode-emoji 15.0-1 (69.2 KiB 993.9 KiB) (Installed)
13 extra/nodejs-emojione 4.5.0-3 (481.7 KiB 6.3 MiB) (Installed)
2 extra/noto-fonts-emoji 20220920-1 (9.0 MiB 9.9 MiB) (Installed)
1 extra/ttf-joypixels 7.0.0-1 (12.0 MiB 12.9 MiB) (Installed)