Same settings under "printer options" and "job options" ?

What is the difference between the settings under "printer options" and "job options" ?

I have found out, that some settings are similar under both tabs, for example for my printer this is:

for the "printer options" tab:
-media size (options: for example: A4210x297mm, A4 AutoDuplex 210x297mm, A4 Borderless 210x297mm, ...)
-print quality (options: normal, draft, best, high-resolution photo)

for the "job options" tab:
-media (options: for example: iso_A4_210x297mm, ...)
-print quality (options: high normal)

1. question: Are this really exactly the same settings under the hood?
2. question: If yes: But why do they not offer EXACTLY the same options? For example for "print quality" I have 4 options in "printer options", but in "job options" I have only 2 options and even the names are different.
3. question: If no: What happens for example, if I choose
   in "printer options" -> "media size" -> "A5" but
   in "job options" -> "media" -> iso_A4
   Or when I choose
   in "printer options" -> "print quality" -> "draft" but
   in "job options" -> "print quality" -> "high" ?
   Do such setting-combinations not contradict each other?

Very interested in this. Thank you.

No source file, test, or entry point is named in the issue. Start by identifying where the printer-options and job-options controls are defined, then verify how their media and print-quality values map to CUPS settings; done means documenting their relationship, available choices, and behavior when they conflict.