Working on a simple game engine

At my part-time teaching job I have some spare time between classes.
So I started again with programming my simple game engine.
It's a project that has been going on for a short while, whenever I have some time and I have nothing else to do.

The engine is being built on OpenGL for rendering, glm for math and physics uses reactphysics3d.
I'm trying to make a simple editor as well using ImGUI.
However, it's not going to be easy as C++ does not have reflection so I'll have to find a way to 'dynamically' allow access to member variables through the editor.
I am aware that Unreal Engine uses C++ and is able to do this, but they have added their own reflection system through their preprocessor header tool.
I will probably stick to some simple macros and require the user to define a lot of stuff manually.