I was thinking about the final ideal in context of Recreance.
First of all, do we know if or how many 5th ideal windrunners existed at that time?
Secondly, the oath is broken when a Radiant act against it. I don't think we know the exact mechanism. I think once there was a WoB when Brandon said it could be broken by either a spren or a humant. So probably just the intent.
So let's imagine a situation that you act in a certain way and accordingly to your oaths. Then you learn about the truth about who is the real voidbringers. In context of new information you realised you were breaking your oaths. Or your actions are not justified anymore by the oaths. And your spren realiesed with you. That's why "WE CHOSE". And still I think we don't know if spren chose or spren AND humans chose.
So, finally, what would be the 5th windrunners ideal that is broken by such circumstances?
I will protect the right ones even if they're not the ones I love
I won't protect if it causes the harm of others
I will protect the rightfull ones
I will know who needs protecting ( similar to "I am law")
edit: I will protect for greater good
(sorry if I messed up some grammar. english is not my first language)