You can disagree but it's a straightforward fact that he has played mostly PF since going to Europe. I've watched him for years. And in terms of objective descriptions, he is written about as a PF by European basketball journos because that's the position he's played.
https://www.euroleaguebasketball.net/euroleague/news/john-brown-as-monaco-basket-interview-best-defender-euroleague/
https://basketnews.com/news-215669-john-brown-close-to-signing-with-crvena-zvezda.html
https://www.eurohoops.net/en/euroleague/1754975/john-brown-officially-joins-crvena-zvezda/
https://www.euroleaguebasketball.net/euroleague/news/5-1-midseason-awards-candidates-best-defender/
https://basketball.eurobasket.com/player/John-Brown-III/233525
https://basketballsphere.com/en/john-brown-olympiacos-its-a-real-rivalry-partizan-its-really-hard-for-me/
https://hedgeout.net/2022/07/17/as-monaco-officially-signs-john-brown-iii-to-a-two-year-deal/
https://sportinground.com/perth-wildcats-to-sign-john-brown-iii/
https://www.euroleaguebasketball.net/news/roster-rundown-unics-kazan/
https://www.youtube.com/watch?v=eFYC-JSWquk
https://www.euroleaguebasketball.net/euroleague/news/marqueematchup-round18-bar-unk/
https://basketball.eurobasket.com/Euroleague/news/747852/Monaco-to-add-John-Brown-III-to-their-roster-ex-Brescia
http://old.scouting4u.com/41,0,0,110566/john-brown-basketball-stats
https://basketnews.com/news-188627-john-brown-laments-missing-dpoy-award-names-euroleagues-biggest-surprise.html
https://www.eurohoops.net/en/euroleague/1296860/john-brown-stealing-the-show/