I just feel I should point out: Having had a housekeeper for a while and watched the expertise that goes into that? I would honestly not call maid "unskilled" work. Honestly true of a lot of labor in general, really.
The term is generally used for jobs that don't require a long formal training to be executed satisfactorily (and can be done with a short period of instruction post-hiring). Certainly, not everyone would be able to do the housekeeping tasks well, but there is no shortage of people who already know how to do housekeeping (because houses are kept clean mostly without hiring specialized workforce), enough so that they can do the job at a basic level. It's not that housekeeping doesn't need any skill, it's that the skill is so prevalent that it's no longer a distinctive skill on the labor market. Same with reading and high-school level maths, or driving a car. It's obviously a set of skilsl, but since most people have these skills, it doesn't turn a job that requires being able to drive, or to read instructions (pick me at my house at 7am then drive me to my office) and to do basic calculation (I have a 40 liters gas tank, it is half empty, I use 6 liters for 100 km, can I drive 500 km without refueling?) into a "skilled" job.
It's probable that most of the readers here wouldn't be able to run a farm, so it might qualify as a skilled occupation in our society. But in a mostly rural, pseudo-medieval society, peasants are common enough that, despite having this knowledge, they would count as unskilled labor. Whereas anyone able to read and write would be considered skilled, while they are not in our society.
The designation doesn't imply a value judgement on the difficulty to do a job, it's a designation relative to the scarcity of the people able to do the needed task, on the job market: can they extract a better pay by virtue of holding this skill, and being rare enough that the supply of workers available to work at minimum wage doesn't satisfy the demand, driving wages up compared to other jobs.