Terminal apps display question marks instead of the € (UTF-8) character and emojis not displayed in Icecat

[danclm]

Hello Guix,
my terminal is displaying question marks instead of the € (UTF-8) character. 
I'm using the DejaVu Sans Mono font, declared as a package in my desktop.scm 
file and configured in .alacritty.yml. The same thing happens with Kitty, Foot 
and other fonts.
fc-cache -rv was executed. I'm running Sway as a window manager.
In Emacs GUI the € character is displayed correctly.
Furthermore, the browser is not displaying emojis properly. Here for example 
https://emojidissector.com/ my browser is showing some square boxes with 
numbers instead of emojis. 
Even if the config I pasted below does not include any package for emojis, I 
had no success trying to declare one and reconfigure everything.

My desktop.scm:

;; This is an operating system configuration template with the Sway window 
manager
(use-modules
(gnu)
(gnu system nss)
(gnu system setuid)
(gnu packages certs)
(gnu packages compression)
(gnu packages disk)
(gnu packages emacs)
(gnu packages finance) ;;legder
(gnu packages fonts)
(gnu packages fontutils)
(gnu packages glib)
(gnu packages games) ;;gtypist
(gnu packages gnome) ;;adwaita-icon-theme
(gnu packages gnupg)
(gnu packages gnuzilla)
(gnu packages gtk)
(gnu packages image) ;;grim
(gnu packages libreoffice)
(gnu packages linux)
(gnu packages package-management)
(gnu packages password-utils)
(gnu packages pulseaudio)
(gnu packages rsync)
(gnu packages ssh)
(gnu packages terminals)
(gnu packages tex)
(gnu packages version-control)
(gnu packages wm) ;;sway ;;waybar
(gnu services dbus)
(gnu services desktop)
(gnu services networking)
(gnu services sddm)
(gnu services sound)
(gnu services ssh))

(operating-system
(host-name "t420")
(timezone "Europe/Rome")
(locale "en_US.utf8")

  ;; Choose US English keyboard layout.
  (keyboard-layout (keyboard-layout "us"))

  ;; Bootloader
  (bootloader (bootloader-configuration
               (bootloader grub-bootloader)
               (terminal-outputs '(console))
               (targets (list "/dev/sda"))
               (keyboard-layout keyboard-layout)))

  ;; Specify a mapped device for the encrypted root partition.
  ;; The UUID is that returned by 'cryptsetup luksUUID'.
  (mapped-devices
   (list (mapped-device
          (source (uuid "8022876e-e0cc-4ec5-8363-0f07c590cdbc"))
          (targets (list "guix-root"))
          (type luks-device-mapping))))

  (file-systems
   (append
    (list (file-system
           (device (file-system-label "guix-root"))
           (mount-point "/")
           (type "ext4")
           (dependencies mapped-devices)))
         %base-file-systems))

  (swap-devices (list
                 (swap-space (target "/swapfile"))))

  ;; Create users and groups.
  (users
   (cons (user-account
          (name "dani")
          (comment "")
          (group "users")
          (home-directory "/home/dani")
          (supplementary-groups '("wheel" "netdev"
                                  "audio" "video" "input")))
         %base-user-accounts))

  ;; This is where we specify system-wide packages.
  (packages
   (append
    (list
     adwaita-icon-theme
     alacritty
     at-spi2-core
     dbus
     emacs
     font-awesome
     fontconfig
     font-dejavu
     fzf
     git
     gnupg
     grim
     gtypist
     icecat
     keepassxc
     ledger
     libreoffice
     light
     nss-certs
     openssh-sans-x
     parted
     pass-otp
     password-store
     pavucontrol
     pinentry
     pulseaudio
     rsync
     slurp
     stow
     sway
     swayidle
     swaylock-effects
     texlive-base
     unzip
     waybar
     zip)
    %base-packages))

  ;; Some programs need to run with “root” privileges, even when they are 
launched by unprivileged users
  (setuid-programs (cons*
                    (setuid-program
                     (program
                      (file-append swaylock-effects "/bin/swaylock")))
  ;; Services
  (services
   (cons*
    (service alsa-service-type
             (alsa-configuration
              (pulseaudio? #t)))
    (dbus-service)
    (service elogind-service-type)
    (service network-manager-service-type)
    (service ntp-service-type)
    (service openssh-service-type
             (openssh-configuration
              (openssh openssh-sans-x)
              (port-number 2222)
              (password-authentication? #f)
              (authorized-keys
               `(("dani" ,(local-file "/home/dani/.ssh/authorized_keys"))))))
             ;  ("root" ,(local-file "~/"))))))
    (service sddm-service-type
       (sddm-configuration
          (auto-login-user "dani")
          (display-server "wayland"))) ;"wayland" ;"sway.desktop"
    (service wpa-supplicant-service-type)
    %base-services))

  ;; Allow resolution of '.local' host names with mDNS.
  (name-service-switch %mdns-host-lookup-nss))

Thanks in advance!--