My problematic is the following. I have a desktop (Ubuntu 18.04) where there is my databases and it can be used as a server. With a trivial laptop using a Linux OS I can easily communicate with my desktop by using Jupyter Notebook connected on it, Mongo and so on. Well using my desktop as force of computing and my laptop as an interface with "poor" computing capacities.
The problem is I don't have laptop now, but I have an Android Tablet Samsung Galaxy Tab A 8.0 (2019). It is compatible and tested with PostmarketOS as far as I know but there is something I dislike: "Beware that by following these instructions, you will overwrite everything that is currently on your device. You will lose all data and it might not be possible to restore the original operating system. There is a risk of hard-bricking your device, meaning it may be impossible to recover without specialist tools. "
This is not what I am looking for. I don't want to replace my Android OS on it which is fine for other purposes. I would like to use it like a desktop where Grub give you the possibility to use the OS you want at the moment. Besides is it possible to install the OS and use it from a microSDcard in order to economize tablet storage's space ? Theoretically an OS can be installed on any storage peripheral storage device (like diskette a long time ago).
I know this is very general and there is maybe better option for the purpose I described at first in this topic. I am open minded about other solutions to answer this need because I am not very aware about all the pros and cons.