Blurb
Porygon2 will be distributed to players via common serial code. Serial code will only work until August 31, 2020.
Broadcast info
Starting at 11am PDT on August 22 and August 23, 2020
Source: https://www.pokemon.com/us/pokemon-news/receive-a-battle-ready-porygon2-celebrating-the-pokemon-players-cup/
During the live stream of the Pokémon Japan Tournament 2020, a Gastrodon based on PJCS2019 Champion's Gastrodon will be given away.
It appears this giveaway only applies during the duration of the livestream. Broadcast Info: Saturday, August 22 Junior category around 10AM JST Senior category around 1PM JST Master category around 16PM JST
(Broadcast links in the source) Source: https://www.pokemon.co.jp/sp/tournament_2020/
You would need to recompile it into x86. Going forward after this year that probably won't be possible, but for now it should work.
You will need visual studio 2019 community. Download the source from GitHub. Then open it with visual studio. Go to the configuration manager and change it to x86. Then hit build. Pkhex.exe is in the bin folder (or search for it).