ACIM feels true to me but is it TRUTH?

So, I found ACIM thru Disappearance of the Universe. Something I’ve been thinking back on is that Gary Renard seems to have injected some of his only ego projects on ACIM. For example - “everything is an illusion” “nothing is real” “forgiveness is THE answer”. I don’t necessarily think some of his absolute statements align with the course. So, my question is, if the course, workbook, etc were Jesus channeled by Helen Schucman then how do we know that she didn’t inject her own ego/bias into it?