What is the best way to optimize a site with loading pages from different sources?

Question

Search Engine Optimization

The site loads content from different sites, as a result, out of 230,000 pages, we have only about 500 pages in the index. How best to set up such loading so that content and pages are perceived as unique? (manually prescribing and changing is not an option, since the bill is hundreds of thousands of pages long). Generate content for each page from different sources? Who faced similar?