What is your current goal and game mode? Is this single player or bnet?
To put it simply, once you have infinity, the number of unbreakable immunes is very low and generally a non-issue.
On Bnet, just trade for Infinity and ask someone to rush you so you can do cows/shenk/eldritch/pindle.
On SP - you can just do LK runs until you get Infinity - estimated: 40~ish hours but largely dependent on your luck.
If neither of these are an option ... well, it'll be a long hard road and Valkyrie isn't really going to change that