Go to ~base install in ubuntu

I relalized that there is no free space in my root parition. I installed a lot of stuff with a lot of libraries but there are became unnecessary now.
What you can do with it ?
I tried to remove all packages what was installed after the first booting.
You can start with the ubuntu manifest file which one is contains the all packages what is necessary for a working system.
Create a packages list from your's computer.
sudo apt list --installed
Download the ubuntu's manifest file from here: https://releases.ubuntu.com/20.04/ubuntu-20.04.1-desktop-amd64.manifest
Make a diff:
diff original.pkgs current.pkgs
Prepare this file with you favorite editor and remove the unnecessary packages. The result should be like this "sudo apt remove --purge ...".
It is not perfect because I have ~4Gb more then the first install was. But it is enough to reach ~10Gb free space in my root partition.
If you have a working script or and other way what you used to use, please let me know :)