So the issue with with Nonduality in this regard to me at least is that you need to prove the effects of the duel system exists. Like yeah, Existence and Non-existence are a thing in Dragon Ball but does Nonduality effects apply? As per our
Nonduality page...
"Nonduality grants the user immunity to attacks and haxes bound by the duality in question, as someone absent of the logical systems that govern those effects would leave them no means to affect their being.
Characters with regular nonduality exist outside and independently of the logical systems that they're nondual regarding without transcending them on any level."
The OP would half to prove that Time Power and Mechikabura are immune to attacks of the existence/non-existent nature because of the dual system and exist outside of it. Sure Time Power encompresses them but other characters who outright exist have interacted with/attended Time Power which would logically be impossible if it had a Nonduality that made it immune to such attempts as those people are bound to the duel system. Plus it also mentions they'd be immune to the dual system being applied to them.
"Besides immunizing them against the dualities in question, this power also immunizes them against attempts to apply those dualities to them, as they would transcend the scope of the haxes that could do so."
Now the page does mention the effects change depending on the verse but those are general descriptions and the Type suggested by the OP is type 1...
"1. Specific Nonduality: Characters existing in a nondual state regarding one or more specific dual systems. This type of nonduality immunizes the user against attacks and haxes bound by the specific dual systems in question."
So as a whole, there needs to be proof that the things/individuals in question are immune to things such as attacks or haxs connected to the dual system in question because of their Nonduality. And looking at TPU
Mechikabura, it seems they could still effect him, they just couldn't kill him without the Key Sword because of his infinite regeneration.
Once again, I'm not saying the Existence and Non-existence duel system isn't a thing, I'm asking for proof the said things in question (Time Power/Mechikabura) actually benefit from some type of immunity to said things in question.