Can we do something to tell more Japanese Pokémon fans about the cut national dex and Masuda's lies regarding the cut?
It seems to me that a lot of Japanese fans don't even know because there has been no official statement and despite the written letter from Masuda also being in Japanese, Japanese fans have no idea it exists because neither the official Pokémon JP Twitter account nor the JP website have posted it.
Sure, some Japanese fans know and have been vocal, but not the majority. Nintendo/TPC are opening pre-orders without telling them that Pokémon are being cut from the game.

Can we go on niconico and spread the message? You can see comments on videos in niconico (if you don't turn the option off). The Pokémon announcement videos all have the comments turned off, just like on YouTube, but there has to be Japanese reaction videos or something where the comments are on. There are other sites, but I don't really know many.
Obviously the message should be in Japanese, so we need someone who is good in Japanese to write for us a short and precise message that says "Pokémon have been cut for Sword and Shield but Game Freak doesn't want Japanese fans to know until the game is bought."
I don't use Reddit or Twitter so I can only make this suggestion here.

I know SwSh fans will think this is petty, but JP fans have the right to at least know as well if they decide to drop the game or not is not my business.