Where can I learn/read about general backend topics?

Question

PHP

Interested in the very general topics of the backend without reference to the language, i.e. routing, caching, form processing, protection against various attacks, the correct use of cookies, sessions, and more. As I understand it, now frameworks / cms provide all this out of the box. And when you need to do it yourself without a framework, there is no longer confidence.
For example, working with forms when you need to edit some user data. Saving this data is not difficult to do. But how to make it so that another user cannot edit them by sending a post request from postmana, substituting the desired id or somewhere, replacing this id with the id of another user, there are already difficulties, in general terms there is an understanding, but there is no certainty . As I understand it, frameworks provide this out of the box.
Or, for example, the layout designer did not want to re-layout a multi-page form after the previous layout designer into a single one (a form of several steps with the ability to return to the previous one) and says, you just save the form field data between steps in cookies or session, or in the database. I say, no, it's better to remake the form in one page and that's it. He says why not? And then I don’t even know why not, I had nothing to answer him with. Perhaps I was wrong and it could have been done that way.
What can be read on this topic?
Perhaps there are some best practices?

Answer 1

Buy Koterov's PHP7 book.
The zoomers howl from her because (there is no video there, and they are not able to perceive the amount of text more than one and a half lines) about the actual PHP there starts approximately from the middle. Just because at first the basic concepts are given there, without which it is impossible to master web programming. Including what is HTTP and how it works.

Answer 2

Or, for example, the layout designer did not want to re-layout a multi-page form after the previous layout designer into a single one (a form of several steps with the ability to return to the previous one) and says, you just save the form field data between steps in cookies or session, or in the database. I say, no, it's better to remake the form in one page and that's it. He says why not?

Do your layout designers define it as correct or do the bosses deal with the business?