Is a higher amount of literature cited in an essay generally seen as better? I'm a postgraduate M.Sc. student at a university studying math. Currently I need to write some essay/assignment (about 10 pages) for a seminar where we revisit already published work and describe it in more detail.
By asking other students about their essay I noticed a great difference in the amount of cited literature. While I use over 30 different resources, most of my fellow students only cite a handful of resources besides their main resource.
Now, it is clear that the quality of literature might vary, and that 30 redundant resources and/or unreviewed resources can be considered as 'bad' resources and sloppy research. But that's not exactly what I mean.
In fact, half of my literature comes from an extensive research on the problem's history and related work (and almost all the literature had been published and reviewed in some way or the other). The other half mainly consists of my 'main' resource for the seminar and some books explaining some higher Matrix calculus and other basics (like the volume of a d-Sphere) which I used to explain the 'main' resource in detail.

My questions are:

Is the amount of literature even noticed by teachers? Do they care as much as I think or do they generally just peek into the literature section and see if it makes sense?

Some of the literature I use has been cited in my original 'main' resource. Is it common practice to just cite them again (which leads to drastically more literature)? Or do I only refer to my main resource even if the statement comes from some other paper?

Does it make a good impression to have a long literature section (with useful and non redundant literature)?

While I love knowledge about the history and related work to a problem it is also much easier than explaining the core of the problem. Do teachers find this stuff interesting at all? I believe teachers are normally very familiar with the problem. My concern is that they are only interested in theory and proofs and might find literature reviews boring. (I did explain the core of the problem as it is important, but I would have done it in more detail if I had spared about a page of history and review.)
The quick answer is yes. Pertinent literature is meant to support your position and build your story. The amount of literature cited usually reflects how deeply and how comprehensively a topic was examined. However, I should say that the literature cited must be highly relevant to be considered as a valid one. It will not be a good practice to pad the cited works to simply give an impression of in-depth research. Experienced readers of academic work will be able to tell if the amount of literature cited actually helps your cause.