I see that a lot of people think this was unnecessary but personally, for me, I was really excited when I found out this version. It shows us a different viewpoint on what would happen. The characters (except katarina) would have different personalities too. And I don't see why there needs to be a "reason" for this to exist, the author and readers(like me) are having fun and that's all that matters lol.
If you think this is unnecessary, you can always not read it :) you're not obligated to read it. Bet ig everyone is curious nonetheless about what will happen in this version.
Isekai + BL? Yes please! So excited that there's finally an isekai bl I can't wait for the next chapters!!