@DeathlyJazzHands55 Why not stick to your original plan for The Mutant Realm instead of listening to others? This is YOUR story and do it exactly as you originally intended! Even if one of your author friends doesn't like it, to hell with them, do what you wanted to do for this story from the beginning! You're the author of your story, not them! You should only listen to their opinion and not change your plans for your story too much because of their criticism of the plot or for fear of "bloating" the plot (which is good for me and shows how much the author loves his own creation and his readers)! After all, you can hardly write this story for more than nine years before your thirties, as you say! And by the way, happy Birthday to you!
We're still going to see The Mutant Realm Saga despite your changes of plans, right? And that Toshiko will become the main antagonist in the MHA Saga, as you originally planned, even despite the changes you will make to the plot starting from Season 3! I think many, if not all, want to see Toshiko Shigaraki, who has grown up for 5 years, end up in MHA after everything she has been through The Human and Demon Realms Sagas and influence the plot of MHA Manga/Anime with various differences at your discretion and become the Main Antagonist and Arch-enemy for Izuku, Amity, AllMight, Bakugo and the entire Class 1-A in general! And if you don't want to write All For Luz for so long, which is frankly a bit insulting, then try to write it more often than your other projects or "cut" some moments from upcoming Arches./The sagas of this story. Again, I hope that you will still achieve everything you have in mind in The Mutant Realm Saga, which is what everyone has been waiting for from this crossover since its release! We believe in you, author, and wish you good luck!