

Conclusion: GOG > Steam/Epic
How much do they pay you?
https://support.gog.com/hc/en-us/articles/212632089-GOG-User-Agreement?product=gog
2.1 We give you and other GOG users the personal right (known legally as a ‘license’) to use GOG services and to download, access and/or stream (depending on the content) and use GOG content. This license is for your personal use. We can stop or suspend this license in some situations, which are explained later on.
We are farther in time from the release of Odyssey than the release of Odyssey was from the release of Galaxy 2.