Thomas wrote Summa Theologica in Latin. There are a number of translations. Estimates are that it would take 50 to 80 hours to complete, depending on how fast one reads. I scan stuff on the internet to get through the material quickly, but I would not scan Summa. I don’t scan the Bible, either. That book requires reflection.
There are many lists of the greatest philosophers of all time. These guys appear on almost every list: Aquinas, Aristotle, Confucius, Descartes, Emerson, Foucault, Hume, Kant, Kierkegaard, Lao-Tzu, Locke, Machiavelli, Marx, Mill, Nietzsche, Plato, Rousseau, Sartre, and Socrates.
The faith enlightened some of them.