Games are fun problems, not optimization problems.

Also, sunk costs are sunk costs. And often the value from spending money is what you learn, not more money.

I could keep building it myself, although it involves much more than just software hours. There is a huge amount of work that includes 2D/3D art, sound, music, networking, UI, onboarding, testing, etc.

There's a reason triple-A games cost billions. When scope exceeds budget, reducing scope is often better. You can build a bicycle much more readily than you can build an airplane.