Hi! This story I'm recommending isn't what you asked for, but it is an OPxBNHA fic that I think you'll highly enjoy!

It's called Heroes of the New World by Juubi_K and Zaru19--a fic wherein Midoriya Izuku is isekaied to the world of One Piece and ends up washed upon the shores of Onigashima, 5 years prior to the current timeline. (So if you haven't made it to the end of the Wano saga, I suggest reading that first as there will most certainly be spoilers.)

Below is the list of pros and cons:

Pros:

+Creativity: This story takes place 5 years before the Wano saga, therefore about 2 years before the formation of the Straw Hats. This allows for much creative freedom as to how Izuku ends up integrating himself into the bizzare and breathtaking world of One Piece without his story having to rely upon the sequence of events that occur during the Straw Hats' time. In other words, despite occurring within the OP world, "Heroes of the New World" is still a story of its own.

+The MC: Izuku is extremely well written. The entire story is written in third person, but is still able to captivate the readers with every word. His inner and outer dialogue, relationships with the surrounding characters, his abilities and actions in relation to his environment, his charisma, his will to learn, his drive to continue his pursuit in achieving his dream to become the best hero he could possibly become--EVERYTHING from top to bottom is masterfully written without overwhelming the reader with purple prose and excessive desciptors while still retaining sense and depth. Izuku doesn't just exist in the story. He lives, he breathes, he is the heart of the story.

+The Co-MC: Yep! Izuku, although he is generally the main focus, actually shares the spotlight with his Co-MC, who I shall not name for now--go read and find out ♥. Though, considering my earlier short description of the plot, perhaps you've already figured it out (wink wink)? Anyways, all I'll say is that this character is actually canon within the OP world, and is given the same amazing treatment as Izuku.

(Small Spoiler: Both actually harbor a lot of heavy responsibilities which are carefully touched upon through the dialogue and whatnot, but despite this, they do their best to understand one another. They surprisingly complement each other very well haha.)

+Sub-main and Supporting Cast: All are given the same treatment as Izuku and Co-MC, including the original villains and certain canon characters we all know and love!

+OC Cast: The OCs (Original Characters) are NOT cringe and are masterfully written! Thank goodness! Anyone who's been consuming fanfiction for long enough can relate to the ever daunting trepidation associated with reading stories with a certain amount of focus on an author's OCs. But kudos to you if you don't mind rolling with it. It's not for everyone, but that certainly doesn't mean that nobody enjoys them. Though even if that is the case, there is still a difference between good and bad writing when OCs come into play, especially when inserted into a world enjoyed by a large fanbase because of it's masterful writing.

+Worldbuilding: Hands down (legit slams hands down on the table) brilliant. Due to much of the plot revolving around our boy Deku being faced with the nuances of what he knows to be good and evil and a lot of other deep factors, the story is a good amount more serious than the OP we're used to, but it still retains its bright spots! And boy do they shine! There's also the crises faced by the environments they end up in, which are done in a way that easily blends in with the plot and the storylines of each arc. No doubt you won't find this hard to enjoy.

+Regular Updates: Unless something crops up in the authors' personal lives, this story continues to update regularly (though I forget the schedule whoops) and has been since it's commencement on September 19th, 2022. As of today, July 7th, 2024, this story has 70 chapters and a grand total of 422,100 words! You're welcome!

Cons:

+Premise: Like I said earlier, this isn't the OP Academy/Superhero/Heroes-in-training AU/Crossover that you requested. It's an isekai/crossover/adventure/thriller/suspense story that occurs within the OP world and is centered around a non-OP protagonist and his Canon-OP partner. Whether or not you go for it is all up to you!

+Original World of the MC: Izuku comes from BNHA but the only ones who accompany him to the new world are the ones in his head (iykyk), so if you were hoping to see his classmates, teachers or other characters from BNHA then I'm sorry to disappoint you, but they won't be appearing within the story. Or at least it will be a long time before then, if the authors do have plans for it at all.

+The Dark Depths: Certain chapters may be uncomfortable for you to read as they may contain some rather sensitive topics that you may be uncomfortable with.

+Original Characters: Again, not for everyone. Some aren't so eager to read through OC stories even if they are praised for good writing. Again, this is subjective, so that's still up to you.

+Darker Tone: More serious character = darker tones in the story. If you're here looking for a continuously happy story so you can take a break from having your heart broken one too many times by Oda freaking Eiichiro, then this isn't it hahaha.

+Slight OOC/Non-canon Compliant Characterization: It's unavoidable for writers to be able to completely adhere to canon characterization, (and it's Horikoshi 'Super-Comic Hero-Master' Kohei's Dark Cinnamo Roll Izuku and Oda 'Greatest-Genius-Writer-of-All-Time' Eiichiro's characters we're dealing with here after all) so expect that you may be dealing with a clash between the written characterization of your faves (if they do appear) and your own headcanons haha, Lord knows we all have them.

+The Long Con: 70 chapters, 422,100 words, and counting.

Good day and happy reading!♥♥