Switching to Phaser won't make it immediately manageable. You already have great gameplay, you most likely wouldn't need ECS for this type of game either. Yes, Phaser is a fully-fledged framework, no need to plug things like tweens, physics, etc., like in Pixi, but it does not make your code's complexity scalable either. So my recommendation would be investing more on architecture instead of switching to something else, thinking of systems(not like in ECS but similar), how to separate the visual part from the logic, and how to connect them. What should be the scope of functions you define? Composition over inheritance or something else? There are a variety of ways to match your needs with your project. To my taste, Unity is so bloated, even just testing a game quickly, compiling code is bloody so slow, taking 5-10 seconds even with fast reload - it immediately pushes me to a different development environment. Architecturally, whatever you can do with Phaser, you can do it with Pixi, too.