The idea that ‘our thoughts are not our own’ is completely incorrect if you have any inkling at all about God and the Christian faith. We are the only beings in Creation that are made in God’s own image and likeness ~ see Genesis 1:26-31. God gave us a garden to live in, and freedom to live in peace and holiness and love. When Adam and Eve fell, by their own free will, we did not give up free will. Lucifer fell by his own free will and became Satan, but he still retained free will, and, knowing what he lost, sought to tempt Man, so that Man would lose God as he did. But God had mercy on us, knowing Satan’s designs, and because we were made in His image and likeness.
Luke 1: 74-75; John 8: 31-36; Romans 8: 15-19; 2 Cor 3:17-18; Catechism of the Catholic Church: part 3, Art 3, I, 1732: “As long as freedom has not bound itself definitively to its ultimate good, which is God, there is a possibility of CHOOSING BETWEEN GOOD AND EVIL, and thus of growing in perfection or of failing and sinning. This freedom characterizes properly human acts. It is the basis of praise or blame, merit or reproach.”
See John 14:5-10. Jesus Himself says that we have the decision to make ~ to believe, or not, to see or not ~ we have a choice, we are free to make our own decision to choose.
To deny that we are free is to negate one of the Cardinal virtues, Hope: Tob 13:8; Joel 3:16; Mark 2:8-9.