The apartment that the maid who the service had sent over was cleaning every week was well decorated.. . . instead, I was wondering, what do you think of the specific topic sentence? Would a native really use it in daily life?
The example sentence is fine. It is one that a native speaker of English would use in daily life. If I were writing it, however, I would change "who" to "whom," since the relative pronoun is functioning as the direct object of "sent over" within the relative clause and should technically, therefore, be in objective case.
It sometimes happens, as here, that a relative clause itself contains another relative clause. Such sentences can be slightly challenging to grasp at times. It seldom happens, though, that a relative clause contains more than one other relative clause. If they are zero relatives, they are very hard to process:
Cheese mice cats catch love stinks.
That example, from a syntax book, is a good example of a sentence with too much embedding and not enough cues to the embedding. Understanding the sentence becomes an academic exercise. Cats catch mice; mice love cheese; that cheese stinks: "[Cheese [that mice [which catch catch] love] stinks]."