Not "basically". It IS the same Mxy... There is only one Mxy across ALL forms of [officially licensed] media.
Comic books, novels, cartoons, video games, toys, etc... It's all the same guy.
It's really nothing new, btw. I've been saying that there aren't different versions of Mxy for over a decade now... AC #975/Jurgens just explicitly confirmed it to the point where even the majority of naysaying moe-rons can no longer argue the fact.
__________________
"I am tired of Earth. These people.
I am tired of being caught in the tangle of their lives."
Doubt it. Wasn't the first company reboot that Mxy has witnessed, and it certainly won't be the last.
You have to keep in mind that multiversal/omniversal shenanigans are so far beneath Mxy that it's hard to fully comprehend. From his perspective it's like watching a bunch of paramecia swimming around in a petri dish(the paramecia = everyone/thing within the mainstream multiverse [inc. it's higher realms], and the petri dish = the entire multiversal superstructure.) The sheer depth and scale of 5th dimensional beings is truly staggering.
That said, the only way I could see Mxy being affected by the events of Death Metal is if it were revealed that Darkest Night/Perpetua/The Hands somehow rewrote or restructured the metafictional process of "imagination" as it pertains to the world of comics(which is essentially what fuels Mxy.) However, the very premise of imagination transcends 'the fictional' and bridges into 'the real'... As Mxy explained/demonstrated here: https://ibb.co/Jjbz1sw
The fundamental concept of imagination is about as meta as it gets... Pretty hard to properly muck with something like that. /shrug
__________________
"I am tired of Earth. These people.
I am tired of being caught in the tangle of their lives."