Is dissatisfaction with the husband's religiosity and fear for the children's well-being due to it a justification for seeking divorce?

Authentic Sunnah prohibited a woman from seeking divorce without a valid reason, and the principle is to prevent the request for divorce except for specific justifications. What you mentioned about your dissatisfaction with his religiosity and his lack of religious authority over you is a general statement. If there is no legitimate reason for seeking divorce, then you are not permitted to proceed with it. You must be patient, maintain a good relationship with your husband, offer mutual advice with wisdom, and supplicate for his well-being. It is not your right to prevent procreation unless there is a strong probability of harm, such as the corruption of children due to living in lands of disbelief. Residing in lands of disbelief entails harms, and it is better for a Muslim to reside in Muslim lands. Hijra becomes obligatory in cases where there is a fear of fitna.