I purchased a new Atlas ESU decoder equipped loco a few years ago and same issue, couldn’t get anything to work, even with my ESU Lokprogrammer. Contacted them, they told me to ship it back, and they replaced the decoder and it was fine afterwards.
Don’t remember how long turnaround took but it wasn’t bad.
Not a knock on Atlas at all, these things slip through once in a while with every mfg.