I didn't get the skin from the 'Ash Free Unlock Bundle' on the Epic Games Store

I fixed this by opening Apex Legends through the Epic Games store, which opens Apex through the EA Launcher.

I just transferred the files from Steam to EA, then launched the game through Epic Games.

Transfer all the files from the Steam folder to C:\EA Desktop\Apex, just create a \Apex folder in the EA one, then copy paste all the files and delete Installscript.vdf and the files with steam tags in them.

Then install Apex on EA, and choose the folder, it will check for all the files before installing the missing ones.