Order of books to read? (Ork related books, and archmagos storyline)

Hi I’m looking for some guidance regarding what books I should read in relation two ‘storylines’ and in what order i should read them in.

Firstly I want to read some of my ork books (brutal kunnin and the latest release Ghazghkull Thraka: Warlord of Warlords) I have already read all the da red gobbo books and Grotsnik. I heard that, although they aren’t an official series, there is some ‘flow’/structure to the books and some other ork books should be read first. What order would you recommend I read? Where do books like da big dakka and Ghazghkull Thraka: Prophet of the Waaagh! Fall in the order?

And secondly, I’m very interested in the mechanicus in relation to lore and books. I have the archmagos book but I’ve heard there’s 2 or 3 books that come before it in the lore timeline. What would you recommend I read before starting archmagos/are related to the book?

Thank you xox