Big Book Changes and Re-release Questions

My first book was epic. Released in 2020, Gorgeous cover, three-parts, 488 pages, 137,000 plus words. I got rave reviews. All ten of them. One problem readers had with it was it’s shear size. I’d show it to them and they’d put their hands up, deer in the headlights eyes, “Oh, I don’t think I could read all that.”

After books two and three were released, I started book four—but I couldn’t get the idea out of my head that book one didn’t deserve to die. I needed to divide and conquer. As it’s a three part book, dividing it into three shorter novels would be easy, right?

I won’t bore you with the details but the endings needed to be expanded for better closure. The beginnings of two and three needed work, and my, my, grandma—how did all those errors and plot holes slip through unnoticed? It’s been a re-edit and in some areas a re-write, and it’s turning out fantastic!

Now, how in the heck do I release my hydra? I want to keep the same cover for book 1 as it’s gorgeous!

Anyway, it’s incredible and embodies part 1 perfectly. The same artist is creating new covers for parts 2 and 3. Now my book has become a trilogy with two new titles. The Dreamers, The Training Ground, and Flight to Terra Nova.

I don’t know whether to take down all the existing books, including The Stowaways, and Flight of the EsCargo and start all over again??? And lose my ten lovely reviews? What would you do?