How to adapt the horizontal and vertical menu for mobile phones?

Question

User interface

Hello dear, here the task was to adapt a rather busy site for mobile phones. What is the point: the site has two menus, one is horizontal (static) in which there are 7 links, the other is vertical (dynamic, changes from page to page). If the horizontal menu can be hidden behind a burger button, then what to do with the vertical one is not clear. Leaving it on its own is a bad option, as there are a lot of links on some pages, and it will not be convenient for the user to scroll through the kilometer-long menu to get to the content.
Are there any cases where this problem has been solved?
Screenshot:
PS: This is a screenshot of the current design, now the site is being redesigned, but in principle the whole structure has remained unchanged.

Answer 1

I speak from the experience of layout of adaptive sites.
The general menu of course asks for a burger. Moving from the side (with a content shift or on top), dropping down.
The sidebar can simply be positioned after the main content. If it's very long and the menu has a lot of meaning to the user, it's not the best solution.
Arrange before content - only if you make it drop-down / sliding out. Look at the filters in adaptive online stores, like dns-shop.ru
In my opinion, this is the most optimal solution.
Hiding it on mobile phones in general is the worst option.

Answer 2

Perhaps we should start by rethinking the usefulness of the current menu items.
How relevant are the sections with information for past seasons and the last century? What sections are the most useful and interesting for visitors, where and how often do they visit (Metrika or Analytics will help here)?
I know from experience that sometimes, by redesigning, you can painlessly abandon the side menus altogether. The site becomes simpler, it becomes easier for visitors, while all the information is still available in full.