Apt proxy - how to keep all packages version


I’d like to use Nexus as Apt repository to ensur that even if packages are removed from Debian official repo, packages will still be present and usable from m’y nexus repository.

I’ve createe the repo and set the Maximum component age and the maximum metadata age to -1.

Is this the good way to reach my goal? Does packages will still be available even if deleted from Debian Source repo?
Does new packages will be accessible even if metadata is never updated due to metadata age set to -1

Thanks for your help and precious advises.