https://www.youtube.com/playlist?list=PLAqhIrjkxbuWI23v9cThs...
He is building new learning materials under his new company "Eureka Labs":
https://eurekalabs.ai
Sebastian Raschka's book "Build a Large Language Model (From Scratch) just released:
https://www.manning.com/books/build-a-large-language-model-f...
All of these resources are excellent.