Changing ubuntu repository via console?

Question

linux

Russian sites are blocked in ukraine and apparently this does not download some packages from the ubuntu off repository, help me how to connect vpn, or it's probably better to change the repository to .com
entered this command 'sudo nano /etc/apt/sources.list' , the list of repositories came out , and there are not only Russians, in general I don’t know how to choose what to do next

Answer 1

Russian sites are blocked in Ukraine and apparently for this reason some packages from the ubuntu off repository are not downloaded,

Ubuntu is not a Russian operating system. The official repositories in Russia are just another mirror.
You obviously have a different problem.

Answer 2

https://repogen.simplylinux.ch/ source list generator for every taste, country and version. take advantage of your health.