https://en.wikipedia.org/wiki/Elephantine_papyri_and_ostraca
https://en.wikipedia.org/wiki/Elephantine_papyri_and_ostraca
The question isn’t whether ancient Israelites worshiped other gods. Every single source we have, including the Bible, says that they did. The real question is how early and how consistently such behavior was objected to, and on what grounds. And there, the evidence shows that even the earliest traditions seem to expect loyalty to YHWH alone, even if they don’t always explain why. Over time, those objections become sharper, more theological, and more absolute. But there is no point in the biblical tradition, early or late, where YHWH is not a jealous God; just as there is no point where he doesn’t have cause to be.
Yes, ok. I'm claiming that the Elephantine papyri show no direct evidence that it was objected to in the late fifth century BC.
There might be more indirect evidence which is more a matter of interpretation, e.g. some claim the other gods' names are really names of aspect of YHW, and it's noteworthy that in the letter petitioning the Jerusalem temple for support in rebuilding the Elephantine temple, no god other than YHW is mentioned. But I think it's hard to make a definitive case either way. Probably the more you look into it the more complicated it becomes, like everything