To what extent are the requirements for layout and URL justified from the point of view of SEO?

Question

Search Engine Optimization

Hello!
Very often, promoters set such tasks, while, in my opinion, as a developer, these requirements are so insignificant and will practically not affect the result that the customer's investment in redesigning the site to meet these requirements will not justify itself.
Here they are:
1) Make section URLs not nested, but from the root. That is, instead of /main/sumki make /sumki .
2) Make the layout of the main menu not in the table, but in the ul-li list, arguing that search engines will better understand that this is a menu. But the fact is that one cannot do without a table, it is needed for the vertical alignment of the text relative to the height of the menu. That is, in fact, you still have to make a table, but in CSS, by the methoddisplay: table-cell
3) The need to get rid of redirects in nested menus. Roughly speaking, there is a 2nd level menu visible only after opening the parent item from the 1st level. Now, for this, a redirect to the first subsection of the 2nd level is used. SEOs say that this is bad...
I would like to know the opinion of professional SEO-optimizers on these points, how important are they for website promotion?

Answer 1

The first two points don't matter at all. The third point, I did not quite understand what does a redirect to a subsection of the 2nd level mean?