good free block theme course

Hello,

Does anyone know a good free block theme course where I can learn to make a block theme from nothing to ready.
So it also learns me what should be in theme,json and what not ?

I tried these two :

https://learn.wordpress.org/course/intermediate-theme-developer/

https://fullsiteediting.com/courses/full-site-editing-for-theme-developers/

but I got the feeling on both I get the pieces but not the whole picture