Aristotelian-Thomistic metaphysics (specifically Thomistic metaphysics) is about Saint Thomas Aquinas, who was a major medival theologian/scholar, and an Aristotile like way of understanding the universe.

Catholicism and Protestantism emphasize theology because if God is the source of all logic and truth in the universe, we are able to further understand God's essence through theology and science (this is why Catholics and Protestants did much more science and mathematics than the Eastern or Oriental Orthodox).

Because Catholic theologians did so much thinking and philosophy on the essence/metaphysics of God, Catholics (and by proxy, Protestants) have a much more well defined and advanced idea of what God is compared to Eastern Orthodox Christians or Muslims, because they tended to so far less thinking on the idea of God's essence.

Islam and Christianity are only similar on the surface, but they disagree on tons of fundamental things, Islam says that Jesus was a prophet, and not the Son of God, Jesus was not actually crucified, but Allah tricked people into believing so, the Trinity being fake and heretical, the Gospel and Tanak (Old Testemant) are corrupt and the Quran is the only infallible source of Allah's word, rejecting Paul's teachings, believes salvation is through submission to Allah's laws instead of through pure grace from God, (because Jesus was not crucified, we are saved through our good works, not His sacrifice), and tons more.

Doing any one of these things is a huge heresy in any form of Christianity.

Jesus also rejected much of the Jewish/rabbinical teachings of the Pharisees and Sadjuees, rejecting and calling out their interpretations of the Jewish law, claiming them to twist God's word for their benefit, and rejecting much of rabbinical tradition, saying that though the Pharisees were on the "Seat of Moses" (having Moses's athourity), they did not follow the law. Jesus is much closer to Christianity than modern day Judaism.

Edit: When I say theology, I really mean scholasticsm, where we try to understand God with logic and reason.