Page deindexing ideas

I have several sites with a very large amount of pages, and starting last year (fourth quarter), tons of pages started getting deindexing.

The sites are built way better then our competition, content, uniqueness, faster, etc.

But month over month the pages are getting Deindexed.

Looking for some ideas please.

Some of the content is copied from government sources, but competitors still show for the same pages.

Checked back links, and disavowed any crappy ones.

All sitemap pages submitted to gwt in 50k urls per map.

All pages inner linked very well.

I'm stumped, the pages were indexed and held for years.

Oh did I mention, zero black hat on them.
Only social media stuff.