The Game Music Toolbox by Marios Aristopoulos is a great introduction into composition techniques for video games. Then, if you want to dig deeper from there, go to Keith Zizza’s Game Audio Fundamentals. It’s broader in scope, with chapters about music theory, soundscape design, tools, and workflows. An excellent source not only if you’re an inspiring game audio professional, but also if you’re a game design lead (or aspire to become one) and want to know more about game audio to keep everything together!
Aristopoulos, Marios. The Game Music Toolbox: Composition Techniques and Production Tools from 20 Iconic Game Soundtracks. Focal P, 2023.
Zizza, Keith. Game Audio Fundamentals: An Introduction to the Theory, Planning, and Practice of Soundscape Creation for Games. Focal P, 2023.