In hindsight, there's a book that sort of covers Data early career, or at least what he was doing when Picard met him. The main focus of the book is Picard's time before the Enterprise. https://memory-beta.fandom.com/wiki/The_Buried_Age
Noone is sure what to make of Data at that point. He is doing some computer database management stuff at some remote location and is content to just do that. Picard shows him how to have aspirations for more.
Starfleet never really thought or cared about Data's needs or wants, let alone sentience, until Maddox wanted to vivisect him
https://redactle.net/ is a fun one