There are dozens of astronauts who've spent years in the space station. Granted that's across multiple missions, but the gravity on Mars might end up being enough to mitigate the damage.
I'm more concerned with the "artist's impression of a Mars colony" being a few low res shapes placed on top of what is very obviously a close up of a few square feet of Martian surface. Have they already outsourced chat GPT's image gen to even cheaper models?
Did you read the article? The research states that based on their findings the astronauts would need dialysis on the way back. How would mars gravity help with that if the damage is already done to the kidney when you get there?
Dozen(s) is not a large enough sample size for long term space impact. Even less, as you've noted, because there are even fewer consecutive streaks.
If you are interested in a sober discussion of some of the known and unknowns surrounding colonizing mars, I would recommend A City on Mars by the Wienersmiths.