That problem has been solved by F2P client/server games a long time ago. The important stuff happens on the server, and the client is "only" a dumb renderer. Yo

That problem has been solved by F2P client/server games a long time ago. The important stuff happens on the server, and the client is "only" a dumb renderer. You'll need to assume that the client is compromised anyway, whether that also means that the client source code "leaks" is irrelevant for monetization (via in-app-purchases, which again is controlled by the server while the client only renders the "shop UI").