@oddish_043. If you enable all mods of the collection, you need to disable Azir. Or maybe you say you only enable this mod on your playset, but you need to enable also the original mod "Runeterra". To be sure, place "Runeterra" on top list of your playset (even if I put dependencies on the mod to say to load this mod after).

How do you actually make this work? It just crashes when I try to run the mod pack here.

I update with the 1.15 technologies.

It's now playable in 1.15.
Note: I don't change the technology branch, still using from the vanilla Runeterra.