I’ve met a number of African Americans who are Jewish. One guys father was adopted by a jewish family, meanwhile his mother’s mother converted long ago. Someone told me once that Jews are a people, not a religion or a race. Sounds like a complex intersection of the two.
Same guy told me that if you convert to Judaism you are Jewish for life. Even if you decide later on to renounce the faith. I think this was part of the plot of the The Big Lebowski, where the Dudes friend converted to Judaism when he got married. However even though the same guy was now long divorced from his Jewish wife, and wasn’t particularly religious, he was super strict about the sabbath and other rules of Judaism. This really perplexed the Dude because he was divorced from the woman he converted for. It’s clear being Jewish was way more complex than that.