Is it permissible to annul the marriage contract immediately after seeing the wife subsequent to the عقد (marriage contract) and the husband feeling that she is not the one who will make him happy, given his fear of wronging her if he completes the marriage, and his parents' desire for the marriage to be completed?

If you can overlook the shortcomings of the girl in a way that does not affect your life together, then we advise you to complete the marriage and seek Allah's help, as divorce may not be the best option. However, if the shortcomings are unbearable, then divorce before consummation and before having children is easier and there is no sin in it when needed. As for a way out for the girl and her parents, that is a matter for you and your family to consult on for an honorable solution.