How to split page content into two pages without losing positions in Google?

Question

Search Engine Optimization

The catalog is located on the main page of the site.
I want to make a separate page for the catalog, how to do it right (transfer the catalog, and keep the rest of the content on the main page) so as not to lose the position of the catalog in Google?
Yandex ignores this directory for the necessary search queries, because of this I want to make changes, but there are other reasons.
The content that remains on the main page is not important for SEO, but it is necessary for site visitors.
301 redirect is not suitable, it is necessary that visitors can get to the main page.
Your own version: Make two pages: site.ru/glavnaya and site.ru/katalog, separate the content on these pages and make a 301 redirect from the site.ru/ page to site.ru/katalog.
On the site, accordingly, change all the necessary links.
And when Google starts issuing a site.ru/katalog page instead of site.ru/ for search queries, remove the 301 redirect and return the content of the site.ru/glavnaya page to the site.ru/ page and make a 301 redirect or, alternatively, make site.ru /glavnaya main by writing in .HTACCESS "DirectoryIndex site.ru/glavnaya".
Can someone suggest something better, or tell me if my version will work.

Answer 1

Alas, no way

Answer 2

I read it 2 times, I did not understand anything.
If the directory is only for SEO, put it on the sitemap page or sitemap.xml. I don't think you are prioritizing correctly.
What kind of valuable information do you have on the main page that people don't need a catalog?
What makes you think that the page ranks because of the directory?

make a 301 redirect from site.ru/ to site.ru/katalog.
On the site, accordingly, change all the necessary links.

Why is a redirect necessary?
What links will change?
A 301 redirect is a change in the url of a page, for example, there was a page: site.ru/category/detal.html, and it became site.ru/detal.html
For a temporary solution, a 302 redirect is used.
In fact, your site had a main page: site.ru, now when you enter the site it redirects to site.ru/catalog
Question for what?
PS. A question out of touch with reality. The desire is understandable. The reason is no.