S&box is not open source neither is its engine - Source 2. Unreal engine will allow for a better future (best engine on market) and Tim Sweeney is open to "crypto" - not far from btc. He always mentions in his interviews that he believes in open standards, interoperability, open source and hates Big Tech. Also UE source is available, but not permissively licensed, Source 2 is a black box.