How to completely clean an Ubuntu distribution of installed packages, leaving only SSH?

Question

ubuntu

I'm trying to set up a home automation server on BananaPro hardware (single-board on an arm processor, Raspberry Pi clone) with SSH control.
But since I'm new - I want to use the Ubuntu repositories and tools.
For this hardware, there are images of various OSes, Ubuntu is only a desktop version, I already figured out how to disable X so as not to load the processor, but the system takes up a lot of space on a flash drive (I use a minimum of 4GB), but I would like to make the most of the available memory space.
And now I can’t find the answer how to remove all packages, reset the system to install only those packages that are necessary for the software to work?
It is not even necessary to leave SSH, it is possible to connect a keyboard and monitor.
Or how to burn a minimal Ubuntu image on that platform?

Answer 1

Ubuntu without X is a Debian distribution. And for the "raspberry" there is a special distribution kit Raspbian.

Answer 2

https://wiki.alpinelinux.org/wiki/Raspberry_Pi
Less than 100MB