I am thinking of switching to Debian from Ubuntu, for various reasons, moving towards a more free software supporting system being one of them. (GNU.org mentions that we can choose to keep Debian completely free if we want, by not including the nonfree repos.)
Apart from the installation (which I should be able to manage since I've grown pretty comfortable around reading manuals and using the terminal) I have one major concern: my internet connection is weak, in terms of both, bandwidth and usage limit. Thus, it would be a huge trouble if I were to download and install all the packages that I'm currently used to using and have set up on Ubuntu, all over again (such as Python3, python-pip packages, GNU Octave and its data, and basically every other package I've installed off the internet using
What I mean to ask is, is there any neat way of doing this? Is it possible, first of all, to take my packages from one system to another, with data? I'm specifically asking because Ubuntu is Debian-based.
If it is not possible after all, I am willing to download the packages (sure, it would take a long time but I would have to do it). But in that case, once I have the packages set up on Debian, can I move just the data across the two systems? Even that would be really convenient.