Finding a working version of that is both "hacked" (with cheats like infinite money or XP) and "no Flash" (playable in modern browsers) is a bit of a hunt, but you have a few solid options: Where to Play (No Flash Required)
When searching for "Feudalism 3 hacked no flash," you will encounter many third-party websites. To stay safe:
After some digging, I managed to find a working version of that runs via emulator (no Flash player needed).
The original version of Feudalism 3, like many online games of its time, relies on Adobe Flash Player. However, the discontinuation of Flash support by major browsers and Adobe itself has rendered such games inaccessible on modern systems. This limitation not only affects gameplay but also restricts the educational potential of the game, making it essential to find alternatives.
Master the Kingdom: Playing Feudalism 3 Hacked Without Flash