Since I believe this, Christianity is off the list of possible compatible belief alternatives. So is Muslim and traditional Jewish, and most others. All people, even you reading this, are good.
Good is a relative term. Relative to me and my life. It is relative to you and your life. Good is a fit with humanism since most non-religious people tend to believe they are generally good.
Behavior is only good or not when it helps reach or maintain quality of life or length of life or attain a goal.
Just because I choose to think of you, or believe, you are good does not mean we are in some “special” relationship or I want to have a nice conversation with you. If you hurt me, I’ll find a way to hurt you back. That is good. We are all good, unless we are gluttons for punishment.
Christianity has nothing to do with “good”, just arbitrary selfish judgement. Christians are good. Their behaviors are atrocious and cause atrocity.
Saying to myself and all others, “you are a good person” is healthy and happy and safe.
Be good is another question. I do judge actions not inherent worth.