What is the ruling on working and residing illegally in European countries, knowing the scarcity of livelihood in one's home country?

A visa represents a covenant and a trust, and Muslims are bound by their conditions. Therefore, it is not permissible to violate the agreed-upon conditions. Earning from such work is not forbidden for the worker as long as the work itself is permissible. As for the impermissibility of working, it is conditional on the workers not being in a state of necessity. Otherwise, it is permissible for them to work to the extent that the necessity is averted, based on the Almighty's saying: "And He has already explained to you what He has forbidden to you, except for that to which you are compelled."