Can anyone fact check this

You could?

But I guess I will.

I can’t find any good source for him having bought Amazon forest. So that’s probably made up. However he seems to be buying and donating to conservation wooded land in the Appalachians.

https://www.treehugger.com/fortnite-founder-sweeney-invests-millions-forest-conservation-north-carolina-4868672

https://www.citizen-times.com/story/news/local/2016/11/08/box-creek-wilderness-permanently-protected/93443704/

https://www.thegamer.com/fortnite-creator-epic-founder-time-sweeney-spending-millions-buying-up-protecting-forests/

https://timesofindia.indiatimes.com/etimes/trending/meet-tim-sweeney-the-epic-games-billionaire-who-quietly-bought-50000-acres-of-forest-to-save-it-from-developers/articleshow/129589611.cms

https://appalachian.org/sahc-south-yellow-mountain-preserve/

In that last one he is being thanked for a particularly large land donation.