Here, I found an instruction on a backup with the built-in backup tool of Ubuntu: https://www.howtogeek.com/108869/how-to-back-up-ubuntu-the-easy-way-with-dj-dup/
However, I was just wondering that if I backed up my entire home folder to an external USB drive, would also all the installed packages and programs (Python3, pip, Opera, ...) be saved in the backup file?
And can I save the backup on a USB where there is an iso file and with which I installed Ubuntu? The USB flash drive has already been formatted.
Furthermore: How much space do I approximately need for the backup, online I read sth about 3 GB?