1. Möglichkeit wird erfolgreich angewendet

snap remove firefox bzw. snap remove --purge firefox
add-apt-repository ppa:mozillateam/ppa
sudo apt update
apt install firefox-esr firefox-esr-locale-de

2. Möglichkeit

snap remove --purge firefox
add-apt-repository ppa:mozillateam/ppa
sudo apt install --target-release 'o=LP-PPA-mozillateam' firefox

sudo nano /etc/apt/preferences.d/mozillateamppa
Package: firefox*
Pin: release o=LP-PPA-mozillateam
Pin-Priority: 501

apt update

3. Möglichkeit

snap list
sudo snap remove firefox
rm -rf ~/Downloads/firefox.tmp/
echo „deb http://downloads.sourceforge.net/project/ubuntuzilla/mozilla/apt all main“ | sudo tee -a /etc/apt/sources.list.d/ubuntuzilla.list > /dev/null
sudo apt-key adv –recv-keys –keyserver keyserver.ubuntu.com 2667CA5C
sudo apt update
sudo apt install firefox-mozilla-build
oder (sudo apt install firefox-esr-mozilla-build)