It isn’t ‘true’ to the books, and as someone who got into sci-fi because of Foundation, that stings a bit- but
the reality is you could never have filmed the source material directly in a multi-season TV series. It was always going to diverge, it was just a question of how.
Its a slow burn, but they’ve made a very good show. My ultimate judgement will depend on how they utilize the Mule storyline, since that is the one that most lends itself to the medium- if they miss out on some of the good story beats available in the original, I’ll be pretty upset.