I really like Andrej Karpathys content

yeah its youtube i know... but, its hand on too

for gpt/llm/ml in general https://karpathy.ai/zero-to-hero.html

it starts with writing back prop from scratch and take you through writing everything you need and training a gpt2 equivalent model in the end

I also thought his lectures at standford, on youtube cs231n 2016, were really good. they cover GAN for generation, but I think after that you can read the papers that were the source for diffusion models dalle and midjouney use