Hint: Learn from the ancients.
As a tactic to create change at a collective level, the use of art is as old as civilization itself. Visit to any ancient city- Rome, Athens, Istanbul- and you’ll see it first hand. Cathedrals, monuments, statues, frescoes etc were all designed to remind people of what actually matters.
Whether the art was talking about a great General or the Emperor Claudius, or more abstract virtues like bravery or holiness, art did it quickly and directly, without the need for mass literacy or advanced technology.
The art was not so much about aesthetics or decoration, but meaning and purpose. It was about the things that actually matter to people. It worked. Powerfully so. The Medicis knew exactly what they were doing.
People become the ideas that surround them.