What is the ruling on marrying a Christian woman with apparent consent to convert the children to Christianity, getting married in a church, and then marrying with a valid Islamic contract, and what should be done after the daughter has been baptized?

You have fallen into calamities due to a forbidden relationship, and passion has blinded you. Marrying a chaste woman from the People of the Book is permissible, but a Muslim woman is preferable. There are concerns about women from the People of the Book in this era. It is not permissible to conduct a marriage contract in a church due to the hearing of disbelief involved therein. Your statement that you do not mind your children being Christian and your signing off on that is an act of disbelief and apostasy from Islam. It is incumbent upon you to repent and return to Islam, strive to rescue your daughter from Christianity, and endeavor to take her to Muslim lands and raise her upon Islam. You are responsible for this daughter and for her disbelief if she becomes Christian.