Thanks, that was very informative. Tweaked a bit with OpenGL and Vulkan at the start of my career. Some VR visualisation software for automobile manufacturers, so I can relate a bit! This is cool that you're so passionate about it :) !
And although I agree with how "unoptimal" popular game engines are in terms of memory usage, GPU draw calls etc... These are pretty secondary issue with modern hardware and it's saving so much production time that I'm happily looking the other way hehe !