Will Yandex correctly index the page on the subdomain with the generated elements?

Question

JavaScript

There is a site that works as follows:
When a client follows a direct link пример: site.com, it determines the client's city by IP, issues information corresponding to the city from the back to the site.
When a client follows a link with a city subdomain пример: subdomian.site.com, I determine the subdomain and display the information corresponding to the subdomain on the site.
Or if the client has chosen from the list, then I save it to localstorage and take the city from there.
So, the problem is that information from the back arrives only after 1 - 1.5 seconds, respectively, with the eyes you can see how the elements of the thought are empty for the first seconds. This raises questions:
Will Yandex correctly understand the content of the page when indexing when there are such delays?
How to coordinate the loading of DOM and information from the back without delays and conflicts?

Answer 1

I can say that such a satst will index worse. Javascript sites out of the box are indexed worse, although Yandex and Google say that they already support them with might and main. I can say that you need to generate a page on the server anyway, if you want to feel normal in the search