Maybe I've been missing out, but can anyone give me a yay/nay on whether this is a worth-while 28-part-series to start from scratch and spend my time watching/reading?

Is it along the same lines as https://github.com/karpathy/llm.c/discussions/677 ?

He (karpathy) has a video series that also does something similar. I found it very informative and entertaining, even at the 1 hour + length it is (there are actually multiple videos, im not sure how long the others are).