This script, based on this source (https://dev.to/darksmile92/get-emojis-working-on-arch-linux-with-noto-fonts-emoji-2a9) should fix emojis showing in apps like Tokodon.

Fix_KDE_emoji.sh

#!/bin/sh
set -e
if [[ $(id -u) -ne 0 ]] ; then echo "Please run as root" ; exit 1 ; fi
echo "Setting up Noto Emoji font..."
# 1 - install  noto-fonts-emoji package
pacman -S noto-fonts-emoji --needed
# pacman -S powerline-fonts --needed
echo "Recommended system font: inconsolata regular (ttf-inconsolata or powerline-fonts)"
# 2 - add font config to /etc/fonts/conf.d/01-notosans.conf
[[ -e /etc/fonts/local.conf ]] && cp /etc/fonts/local.conf /etc/fonts/local.conf.bak
echo "<?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>
     <family>DejaVu Sans</family>
   </prefer> 
 </alias>

 <alias>
   <family>serif</family>
   <prefer>
     <family>Noto Serif</family>
     <family>Noto Color Emoji</family>
     <family>Noto Emoji</family>
     <family>DejaVu Serif</family>
   </prefer>
 </alias>

 <alias>
  <family>monospace</family>
  <prefer>
    <family>Noto Mono</family>
    <family>Noto Color Emoji</family>
    <family>Noto Emoji</family>
    <family>DejaVu Sans Mono</family>
   </prefer>
 </alias>
</fontconfig>

" > /etc/fonts/local.conf
# 3 - update font cache via fc-cache
fc-cache
echo "Noto Emoji Font installed! You may need to restart applications like chrome. If chrome displays no symbols or no letters, your default font contains emojis."
echo "consider inconsolata regular"