Try one command at a time:
export DISTRO="focal"
sudo curl https://repo.waydro.id/waydroid.gpg > /usr/share/keyrings/waydroid.gpg
sudo echo "deb [signed-by=/usr/share/keyrings/waydroid.gpg] https://repo.waydro.id/ $DISTRO main" > /etc/apt/sources.list.d/waydroid.list
sudo apt update