I am loving Godot. It is MIT-licensed, under very active use and development, and allows effortless deployment to Android, iOS, Windows, macOS, Linux, and Web.
https://godotengine.org/
I would consider it for any kind of cross-platform development, not just games.
It supports Vulkan, Metal, Direct3D 12, OpenGL and WebGL (but successfully hides all that): https://docs.godotengine.org/en/stable/contributing/development/core_and_modules/internal_rendering_architecture.html

