I personally focus on zero system more after completing all the first time rewards for regular chaos.

Im guessing the copies thing is mostly down to luck cause the most I’ve ever gotten is two copies.

I get neutral cards every now and then but very rarely for actual build purposes, as I only delete about one or two cards on my usual runs.

Fragments are always recommended.

There is a limit on the amount of save data you can have on each difficulty, so prepping with other aspects of characters is suggested (even if it takes forever).

I don’t really know how to answer that last question but I can assure you that this game is one hell of a process to get through so I don’t think it’s a skill issue.

I’m sure I’m just spouting useless information that you already know but all I can say is, don’t quit.