I agree, the "overcomers" are those who have faith that Jesus is who He said He was. We do not "earn" salvation.
Perhaps, though, "overcomers" earn "rewards" by doing God's will through their efforts. I don't have any idea what "rewards" is.
Some folks have gone astray a bit by describing the add-on rewards for heroic Christian living. Like being a "special person"
in the Millennium or in Heaven. Some people may be special but I do not think the scriptures tells us that. We are all saved by
grace, special or not. Because of the apparent delay of His coming, people are getting antsy and adding on things.
If we get a reward for being patient in tribulation, I expect it will be lovely. But I don't know about it yet. It is a surprise. Every
revelation of God that I've had has come as a surprise. He's just full of them!