The below task need to be completed before you login via the GUI!
Edit:
nano /etc/apt/sources.list
Add the below line.
# Not for production use
deb http://download.proxmox.com/debian bullseye pve-no-subscription
Now disable the enterprise repo.
cd /etc/apt/sources.list.d
cp pve-enterprise.list pve-enterprise.list.bak
Edit:
nano pve-enterprise.list
# comment out this line : deb https://enterprise.proxmox.com/debian/pve buster pve-enterprise
Update the system.
apt update
Run Distro Upgrade.
apt dist-upgrade -y
When done reboot the server.
reboot
sed -Ezi.bak "s/(Ext.Msg.show\(\{\s+title: gettext\('No valid sub)/void\(\{ \/\/\1/g" /usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.js && systemctl restart pveproxy.service
bash <(curl -s https://raw.githubusercontent.com/Weilbyte/PVEDiscordDark/master/PVEDiscordDark.sh ) install