Inflation being a monetary problem

What is the most compelling evidence that government inference (increasing money supply, over regulating supply chain, etc.) is the main cause of inflation and not the arbitrary “greed” of businesses? I have some friends who are mystified at the prevailing high levels of inflation despite the Keynesian actions of the last four years. What would be convincing to show to someone of that economic persuasion? As someone who subscribes to the Austrian and Chicago school style of economics, it feels painfully obvious to me that this is a government and monetary issue.