The Boku no Hero manga is way ahead. It continues to expand the world and story beyond what's presented in the anime. But both the manga and anime have their own charm and appeal to fans.
The anime of Boku no Hero Academia roughly ends around a certain point in the manga, but it's not an exact match. There are some differences and adjustments made for the adaptation.
Since I haven't read 'boku girl boku no arbeit novel' directly, I can only speculate. However, from the title, it might deal with the concept of identity ('boku girl' could imply something about gender identity or self - perception). Also, 'arbeit' might suggest themes related to work or purpose in life. There could also be themes of personal growth and the challenges one faces in the context of work and self - identity.
One similar novel could be 'Kimi no Na wa' (Your Name). It has a unique story about two people who mysteriously swap bodies and their journey to understand each other. Another might be 'Orange' which also deals with complex relationships and personal growth in a rather poignant way. And 'A Silent Voice' is also a great choice as it focuses on themes of redemption and friendship like many good novels in this genre.
Well, 'boku no fanfic' might be a fanfic written from the perspective of 'boku'. It could be a creative piece that takes elements from an existing story or world. For example, if it's related to a popular anime, it might expand on certain storylines, develop side characters more, or explore different relationships within that anime's universe. But again, without further details, it's hard to say exactly what it's about.
The Boku no Hero manga is finished. It reached its conclusion after a successful run, leaving fans with a complete narrative and memories of an exciting journey.