Am I obligated to obey my father who prevents me from going to the mosque for prayer, under the pretext of fearing for me due to security concerns and surveillance by security agencies, knowing that the mosque is nearby? And is praying in congregation at home sufficient to count as praying at the mosque?

Your congregational prayer at home is valid and fulfills the obligation. The jurists have stipulated that a son is obligated to delay prayer if his father commands him to do so, in order for the father to lead him in prayer. If he forsakes the virtue of praying at the beginning of the time out of obedience to his father, then similarly, he should forsake the virtue of congregational prayer in the mosque. Therefore, you must obey your father and pray in congregation at home as long as his fears persist. Then, speak to him gently and kindly, and explain to him that many people go to the mosques without any harm befalling them. Continue doing so until he is pleased and comfortable with your going.