What is the ruling on migrating from Muslim countries to non-Muslim European countries in pursuit of a decent life, a monthly salary, education, and healthcare, while fearing for one's children from being lost in those infidel countries?

If it is not possible to find work in your country and circumstances are difficult, and you are able to work in European countries while ensuring the safety of yourself, your family, and your children from temptations, and you are able to perform the rituals of Islam, then there is no harm in residing there with the intention of returning to a Muslim country when circumstances allow. However, if you are not safe from religious temptation, then it is not permissible to reside in non-Muslim countries.