Why yes we are!
We believe all of that comes from Christ himself, not Gaia, or Buddha or a Golden Calf.
I can see that you are a Bible believing Christian and so am I. We both interpret scripture differently. No have no proof that you are absolutely right. Neither do I. And I am not going to be prideful and state that another human won't make it to heaven because of my beliefs.
I don't know the mind of God. Neither do you.
I don’t believe I have said anyone is not going to heaven. You are right, that is God’s domain.
But the bible clearly states we can judge teachings to be correct or not. The bible is also clear on it’s teachings about salvation. So, put those two together and we can know and accept or reject as true or false things that are taught.
Motive is the key. Why do Catholics partake of their sacraments?