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Most of the repositories and PPAs in your sources.list are no longer available and are throwing errors. I d recommend restoring the default repositories.
First, restore the default focal repositories using these commands:
mkdir ~/solution
cd ~/solution/
cat << EOF > ~/solution/sources.list
deb http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
deb http://archive.canonical.com/ubuntu focal partner
deb-src http://archive.canonical.com/ubuntu focal partner
EOF
sudo rm /etc/apt/sources.list
sudo cp ~/solution/sources.list /etc/apt/sources.list
Remove all the PPAs in your system:
sudo mv /etc/apt/sources.list.d/* ~/solution
Update the repositories:
sudo apt update
Now there should be no errors.