Javascript and ajax, how much do they interfere with SEO?

Question

CMS

In general, there is a site on a foreign engine
The content of the page itself is loaded using javascript
The content is pictures + title + alt + links to their "page" The
page, in turn, is a full-fledged static html
How will such a site float among search engines and how competitive is
it planned at launch 2500 pages
The site is image-oriented, with a nice design and functionality, almost sure that the user will want to return.
What tips can you give to optimize such a site?

Answer 1

The best way is not to use ajax.
Crutches:
Google: https://developers.google.com/webmasters/ajax-crawling/
Yandex: https://help.yandex.ru/webmaster/robot-workings/aj...

Answer 2

Give the search engine the version without Ajax, and for the user with Ajax