Dull, irksome, and fatiguing work : uninspiring or menial labour. (Merriam – Webster)
Hard boring work. (Cambridge Dictionary)
You use drudgery to refer to jobs and tasks which are boring or unpleasant but which must be done. (Collins Dictionary)
Menial, distasteful, dull, or hard work. (Dictionary.com)
Drudgery: How to Take it Out of Your Day.
The Drudgery of Modern Work.