The modules won’t work unless the current version of the kernel is the same as the one on the ISO. So, it will only work if you happen to have a band-new ISO.
It is surprisingly easy to do this on Manjaro. There is a video on how to do it that philm made here: https://www.youtube.com/watch?v=B--je--m0VI
Just use one of the existing profiles and add the spl and zfs modules. Since you are doing an architect install, it doesn’t really matter which profile you use.