[_gabe_]

Math books can be a hit or a miss, but Game Engine Architecture is an amazing overview of all the major systems in a game engine. You’d also be doing yourself a disservice if you didn’t read something like OpenGL Superbible (that book filled in so many gaps in my knowledge and made graphics development so much easier).

As for the rest of your comment I absolutely agree. I wouldn’t discourage anybody from trying to write a game from scratch, but if you want to focus on art style, level design, game mechanics, and being able to easily ship to almost every platform, then I would definitely encourage you to use an engine like Unreal or Unity.

OP made it sound like Hollow Knight could’ve been a great game if only they didn’t use Unity, but I don’t believe that. It is a great game, full stop. It’s like people that complain about electron (which I also tend to agree with) irregardless of whether the final product is any good or not. VSCode is great, in spite of the fact that it was written in Electron. And ultimately, the people buying your games really won’t care how it was made, they’ll just care about how it plays.