Dubious evidence. DNA testing has my pasty White, German-Dutch-Welsh surnamed wife (traceably going back generations) as 20% Ashkenazi jew. That would mean her grandparents were either half jew each or one was full jew, which is demonstrably false. There is no significant jewish presence in her family history as far back as we can trace.
It just means you have DNA that's similar to people with that heritage. So it's to be taken with a grain of salt alongside other evidence.
So when taken alongside Columbus's writings, historical documents, maps, accounts from the time... most likely Columbus was from Italy. He's got similar DNA sequences to jews, so what? He's got similar DNA sequences to chimps too; he wasn't a chimp.
When he left they made a nasty sign about him, so he brought in the Battleship New Jersey and called in a shore bombardment with 16 inch naval guns from 20 miles offshore.
https://www.bbc.com/news/articles/ckg2049ezpko
https://edition.cnn.com/2024/10/13/world/columbus-origins-western-europe-study-intl/index.html
https://www.timesofisrael.com/study-finds-christopher-columbus-was-a-sephardic-jew-from-western-europe/
https://www.myjewishlearning.com/article/destination-the-new-world/