I don't think LeBron will end his career with the Cavs. He used to really want to win a title with the Cavs, and he did so in 2016. But now I don't see any particular reason why LeBron would suddenly decide to move to the Cavs, especially if he is determined to win another ring.
What’s wrong with the Cavs? This team isn’t weak anymore, they’ve shown they can finish the season with a solid record, even better than LeBron’s current team. So there’s a real chance he could win a championship with them if he comes back. Imagine if he joins, the Cavs won’t just be focused on Mitchell anymore. They’d have a combo similar to Wade and LeBron back in the day, and I think that would make them a strong contender.