Yea im a little surprised at how small the data has to be for a godot game . I remember you said that you were going to Unity . Is that ecosystem any better.
I said I was "tempted" to go back to Unity. But I recall it's not necessarily the engine you work with, but how you're able to adapt systems for your use. Certain features help, and engines will have their strengths, but there will be limitations to overcome anywhere.
Had my issues with the corporate business dealings and bloated backend of Unity that it's tough not to continue with Godot's approachability and open-source structure.
Unhelped, my own ambitious ideas could probably use some realistic downscaling. I'm no wizard with code. But some inspiration seeing other game devs push the limits of optimization to fit games on a small file size.