Why are these fields in control when building a deb package?

Question

linux

I studied the structure of deb packages, and the following questions arose:
What is the difference between the Recommends and Suggests fields? (both in that and in another field is a list of recommended packages)
Why is the priority field needed, where is it checked / used?
Why do we need packages that can be installed but not removed?
Why do you need the Essential field if you can disable the removal of the package through Priority?
Is it still possible to remove the package and how if Essential = yes or Priority = required?

Answer 1

How are the Recommends and Suggests fields different?

https://www.debian.org/doc/debian-policy/ch-relati...
https://www.debian.org/doc/manuals/debian-faq/ch-p...
TL;DR: strength of recommendation (Recommends are stronger).
https://www.debian.org/doc/debian-policy/ch-archiv...
So that the user does not break the system with a fool.
https://www.debian.org/doc/debian-policy/ch-control...
Priority = required - as I understand it - yes, Essential = yes - as I understand it - no.