do you think that skilled slaves had advantages over other slaves?

Well, yes, in general. If a slave knew how to do something that was of extra value to their owner/master, and hard to replace, then it is possible that they might be granted more leniency and flexibility than another slave that might be easier to replace. Depending on the owner though, all slaves could be working with a fear motivation and punished regularly for disobedience. In other cases, an owner would treat slaves more like family, having grown up with them... expecting deference, but also allowing for personalities and the occasional refusal. Also, in general, slaves were a large investment, and theirs lives typically wouldn't be thrown away for nothing... skilled slaves, especially with skills where they could be in the house during the day rather than in the fields, might help them to learn more and survive or even escape, depending on the circumstance.