Transduality in vs battles basically acts as an extra layer of "You can't touch me" similar to NEP, Abstracy Existence, Incorporeality, etc.
Transduality Type 1 is being beyond one to three dualities. As you mentioned that includes the duality of life and death, as well as others like reality and fantasy, hot and cold, etc. This makes you essentially resistant to any degree of whatever dualities you are beyond.
Of course, this means nothing to higher dimensions and they can still use Death Manip on you even if you are beyond its duality.
Transduality Type 2 is beyond all dualities within a certain level of reality, the level of reality is referring to whatever extent the verse says the ability extends to. This is basically resistance to everything present in your verse and therefore very useful in battles. But like Transduality Type 1 it doesn't matter to higher dimensions and they can just affect you anyway.
Transduality Type 3 is similar to Type 2 beyond all dualities but also follows many-valued logic. For example, take the Duality of Hot and Cold. You can be Hot, you can be Cold, you can be both Hot and Cold, or you can be neither Hot nor Cold. Someone who has Transduality Type 3 would not fit into any of those states, while someone with Transduality Type 2 would.
