With nitrogen steel we can have it all except cost. That's why you don't see it being used.
The limits of nitrogen steel have not been explored, there really isn't any high alloy A11 class nitrogen steels readily available.
There was Vancron 40 and Vanax 75 but they aren't currently available in useable sizes for knives and are even more expensive the Vanax Superclean.
Uddeholm is currently the nitrogen steel leader but they are more concerned with balance, not extremes.
People forget that Extreme performance is Extreme trade off.
Those of us that understand that get that performance if we play to the steels strength and avoid it's weaknesses in use, sharpening and hopefully the knife's design/desiger takes advantage of it.
However, that's the beauty of high nitrogen, high carbon, high Vanadium.
It's more balanced then it's non-nitrogen cousin, Easier to sharpen and more stable but less horsepower (still won't out cut 15v and rex121)
Just extremely expensive.
You'll probably see steels like this in production knives by 2030ish
It takes a while for production to catch up.
To the OP, all the most Extreme steels exist right now, 15v, s125v, Rex121
No one is using them for many reasons.
They are a nightmare to work with and a nightmare for users that don't understand the trade off's