Yes, using Abdul is a stereotype. No, it's not politically correct. It's also unfortunately not historically inaccurate.
If you were anywhere near the Mediterranean in medieval times and walked into a slaver's business, there's a fair chance there was an Abdul or culturally similarly named person there. If you went far enough north, that name was probably more likely to be a Ragnar, or something similar. Slavery existed in many medieval cultures. Particularly the more cosmopolitan ones. When you don't have technology, all the hard labor has to be done by animals or people. Whether or not said people want to do it didn't always figure into the discussion. That's why it shows up so often in fantasy and isekai anime. It's a simple way to show a massive cultural difference, not to mention an easy path to any number of plot points.
The Japanese tend to be less sensitive about that kind of thing than people in the West, unless of course it's about some of the darker times in Japanese history...