tried
sudo apt update && sudo apt upgrade -y
sudo apt install update-manager-core
sudo do-release-upgrade

Checking for a new Ubuntu release
No new release found.

Checking for a new Ubuntu

How to Install Ubuntu Server 22.04 on Proxmox? – GetLabsDone

If you want to test Ubuntu or install it on your system, you can use a USB drive. Learn how to create a bootable Ubuntu USB in Windows.