The Truth is timeless.
Heresy is a fad. (e.g. mad made traditions like Sola Scriptura)
Truth is timeless, but powerful and political factions deem what is truth.
I respect that your particular flavor of religion claims to have the monopoly on truth, but others who disagree do as well.
So what is truth?
With religious matters it’s hard to tell. These things are not largely subject to scientific scrutiny. You know it’s “true” because you believe it. And your church supports your belief.
Other denominations or religions view your beliefs as heresy.
Those beliefs are not able to be proven or disproven. They all come from a belief from what is not seen. Truth in religious matters may be timeless, but they’re also unprovable, which makes the charge of heresy somewhat arrogant.