It's yo boi Burger Ben, here to leak.

Pokemon Sword and Shield was originally intended for the 3DS, and then later Mobile. GameFreak seriously did not believe in the Nintendo Switch. The expectation was the Switch would flop horrendously and Nintendo would retreat to the 3DS before ultimately becoming a Mobile developer.

Pokemon Let's Go Pikachu/Eevee was nothing more than the canary in the coal mine, it was released with the expectation of flopping in order to justify to Nintendo a decision to keep away from the Switch. I mean shit, the game literally doesn't have fainting animations.

When Let's Go sold like hotcakes and the Switch overperformed GameFreak was in a scramble to get Sword and Shield onto Switch in time for a Holiday Release.

The version of Sword and Shield you have is taken from a Beta that's been ported twice (first
to Mobile then Switch), and is literally not finished.

This is part of the reason all the excuses for Dexit were only released to the US, it was a marketing guy feeding shit to the director. The whole "National Dex is how it works now! Pokemon Home is a Pokemon Prison!" was a lie.

Sword and Shield being Commericially Available Betas is also part of why the Dex Cuts seem random as hell.

Like for example why you can buy a shirt of Poliwag in the first town, yet that's not in the game.

Why you can make Slowpoke Tail curry, but there's no Slowpoke.

Why the poster in your home lists Machamp, Gengar, and Charizard as Galar Region Pokemon (The poster was a placeholder)
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A complete version of Sword and Shield (with a new story and a playable Kalos Region) called "Sacred Sword" and "Sacred Shield" will becoming with a similar story.

Kalos is your Post-Game, much in the same way Kanto was in Pokemon Gold and Silver.

There will be Kalos Region Variants who are plot excused by a Calamity happened in Kalos.

This Calamity will also be the reason why you can Dynamax outside of Galar (for the rest of the series)