Massively overblown.
It's supposed to be a book about effective technical decision making, but TBH (if you don't want to do "babysitting"), it's a topic for a series of posts at-most. So the author has decided to become Cpt. Obvious and provide very literal recipes for truly trivial things. Honestly, if you need this level of detail (& can't figure it out yourself / make it happen), you have a very serious problem of a different sort ...
The 1st part is about architectural decisions and ADRs - it's fairly OK-ish. Then he moves towards giving arch. advice and decentralization of decision-making. I had an impression that one good article on RACI matrix covers this topic much better (with a higher clarity and actionability). Then he moves towards very enterprisey constructs (that TBH don't address the underlying issue, just walk it around) like - architecture advice forum or tech radars ... The next section is about arch. principles - and again - personally I think it's a very valuable & important topic, but somehow the true essence of its meaning is lost in the oververbose content ;(
In the final section the book surprisingly (?) redirects into leadership (!) and culture areas. Yes, they ARE related (culture should impact the decision making), but it feels mostly like a preaching fluff - one can write about leadership ad infinitum but it should truly correspond to the core topic of the book.
IMHO there's a massive amount of work put into this book. And I'm not questioning the knowledge and experience of the author. But writing a good book is something entirely different that just capturing one's knowledge - more deliberate work is needed to extract what's truly essential and build it into some focused "story". This part hasn't been covered here well.
It's a solid 3.2 (rounded down), but you can easily add 0.5-0.7 point if you don't read it end-to-end and just skim to the specific section you'd like to confront your knowledge against.