[ubuntu] ubuntu 22.04 apt-get update 404 error

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

이거 해결한다고 3시간동안 삽질