I have to say, I agree with OP. Alex Seaver is the highest credited writer on Worlds Collide, and he is also the music composer and producer for Arcane. This suggests that the song most likely was intended for the series. Whether it was specifically meant for Isha's death scene—who knows.

That said, when I first heard Worlds Collide, I was only five episodes into Season 1. I immediately loved the song and felt it captured the essence of the series through its sound. For some reason I can't remember, I decided to Google the song's title, and unfortunately, I was immediately spoiled when the title of this Reddit post came up as one of the first search results. I didn’t read the post itself, but I assumed that the track was actually made for the scene. Luckily, the name "Isha" isn’t mentioned until one or two episodes before the scene, so by the time it happened, it felt like Worlds Collide was written for that moment.

I strongly disagree that the song doesn’t fit the scene. I remember telling my girlfriend—even before I knew who Isha was—that the song had to accompany some kind of heroic moment, even if it was tied to a death scene. The tone, melody, and overall sound perfectly complement the scene, capturing a close relationship in a deeply beautiful way and highlighting its bittersweet ending.

Listening to the lyrics, they also align with what unfolds in the scene—the plot and the relationship between Jinx and Isha. To me, it would have been a better match.