to be clear a i mistyped, "but through vague research, they are the same"
and to be more clear i misremembered the wording
in some ways sillier than how i remembered it, if I'm being hoenst
It's silly cause they keep using wishy-washy language. "Theorized". "Think". "Believed". Nothing concrete, if they say anything definite they have to then mention the source is vague. And the main is they keep emphasizing it. The Galarian Birds aren't treated as their own trio, they're treated as a mystery connected to the Legendary Birds. "Why do they look different"? "Are they a variant or just happen to look alike"? Meanwhile their opening cutscene shows them eating the fruit of a tree which has relation to the Dynamax phenomenon. Um, why not explore that side of the mystery? The tree seems pretty odd, and the fact that it grows fruit which seems to be able to alter a Pokemon's being upon eating it I think would yield some answers about the birds if we had focused the mystery on it. But no, instead it's just used as a set piece and then a joke Dynamax battle.
The main problem is pretty much a problem the Legendary Pokemon have been having recently: special status. The reason scientists can't definitely confirm whether the Legendary Birds and Galarian Birds are related is because they can't get their hands on any. They're ~
Legendary~ Pokemon, not just anyone can catch them. Now please ignore all the trainers who in the past have caught one, especially the NPCs. Their Battle Facility teams don't exist in canon, why would you think it does? And even if a NPC is definitely shown having a Legendary, well I guess science is just not interested in examining that Legendary at the moment. Or we got to keep it a secret. Like it's one thing if the Legendary doesn't want to be examined, like I imagine the Island Guardians to be a bit fickle and not want to be bothered, but as long as you're not hurting them I think most Legendaries under a trainer's control would be "yeah, sure, whatever".
Speaking of Poké Balls, I've been under the impression that the reason why people thought Pokémon were converted to energy inside Poké Balls was because of the anime; when a Pokémon is sent out or recalled, they turn into/form out of white light. I wonder if they tried having Pokémon shrink, but it was too hard to animate and/or they couldn't make it look good?
If we go by that pre-release booklet for Gen I, it was originally thought that the Pokemon just shrank when they went into a Poke Ball. Back in Gen I the only thing we saw in the games was puffs of smoke when a Poke Ball is thrown (whether to capture or releasing a Pokemon) and the Pokemon sliding off screen in a certain direction otherwise (sliding to the side if recalled or down if knocked out). As
Karxrida pointed out, it was this explanation that was used in the Adventure and other Pokemon Manga at that time.
In comes the anime, and while showing a Pokemon changing size isn't impossible, it would be more costly. So instead, being the Pokemon World is more hi-tech, they took the shortcut that the Pokemon aren't changing size but rather being converted into energy. Now all they need to do to show a Pokemon being put into its Poke Ball is a red line from the Poke Ball and the last frame of the Pokemon just turning into a red silhouette before vanishing. Simple, cost effective, and in my opinion much better of an idea. (FUN FACT: This is pretty much the reason Star Trek has transporters, cheaper to just do a fade in & out effect than making a shuttle craft model fly to and from the starship/planet/space thing)
I actually base it more off of the other tech available in the setting, specifically the PC and warp tiles. The fact that mons and items are stored in a computer implies that they are capable of being converted to/from data, while the warp tiles have me thinking of the Star Trek transporter, which also used energy conversion.
Shrinking/Enlarging to the extent they would need to with a Poke Ball would also be an example of advance technology. If they stuck to the Pokemon changing size thing the PC and Teleporters could easily be explained away. For the Transporters it's only a momentary transfer done at the speed of light, and it could also not be mass-to-energy but a bending/folding of space which only looks like a flash of light. The PC actually connects to a physical storage system somewhere and Poke Balls are just being transported to and from it, likely having automated systems to make sure things are orderly.
Heck, the anime that seemingly how PC storage works. Professor Oak stores all Kanto trainers Pokemon in his lab (he at least has all of Ash's and Gary's) and Pokemon Centers keep Poke Balls physically on shelves until their trainers come and pick them up.