The cohesion of all this is way too weird. Maybe it's more than just Carbink, Diancie and Deoxys. Are paradox Pokemon simply mutations like Diancie and Deoxys? After further research, the well runs much deeper than just "Diancie is a Paradox Carbink lol!"
(Totally derailing here, but I'm too invested to make a separate post by this point)
I now have a theory for "a virus in space caused AZ's weapon to misfire, creating Deoxys, blasting a hole in Paldea, creating the Darkest Day in Galar thus ending the war between Galar and Unova, and creating Mega Evolution as well as probably Terastalization"
(This is going to be my last addition to this post for a while now unless I find more important connections)
This can't be coincidental because X&Y got delayed TWICE due to Gamefreak also making BW2 along side Gen 6. So, we know this has been planned out since, like, at least Gen 5. Especially since we know about the story between the original dragons, the 2 princes from Unova, and that at the time of the Darkest Day, Galar's royalty was at war with another region, probably Unova's fallen kingdom.
A bit off topic again, but I always thought it was weird that Iris's origins are incredibly vague and ominous, and she looks jarringly similar to Leon from Galar. And, Iris's champion chamber is literally a throne room. And they both use a Haxorus. Idk what it means but something is there.
I got so off topic, but in conclusion:
Something big is coming for Gen 10 and those Unova remakes, and I think Diancie and Carbink are gonna be a big part of SV's DLC. And, if this connects to Mega Evolution, we might actually end up getting an explanation for all those "unfinished/unexplained" tid bits in X&Y. My only other theory is that there was a second weapon created in Paldea but i have no evidence for that besides the Gracia Stones.
What the fuck are you planning Gamefreak?
Edit: I think this is more purposeful than I originally realized. Here's a separate post I made regarding N and Iris and how I think N is actually from Kalos and Iris might be too (but Iris is much less likely).