Low page indexing + drop of indexed pages

[MichaelGin]

Hi,
I have a couple of questions and your advices will be very much appreciated.
1) Indexed pages
GSC show that only 20000 from 60000 in sitemap are indexed
Index status show there were 140 000 indexed pages. During last year it droped to 59 000
Site command in google search shows 27 000 results.
I assume 59 000 in Index status is old results (probably show previously indexed seach results pages etc.
But 40 000 real pages from the sitemap still not indexed
I submitted this new sitemap 6 months ago.
Any suggestions? What could be done?
(all basic things checked, robot txt, parameters etc)
(same happen for all websites including mobile)

2) We have marked up tens of thousands of pages with event structured dada, breadcrumbs etc.
But almost nothing appear in the Google search results. Some of the were crawled and appear in th Structured Data report/
Any suggestions? What could be done?
Thanks,
Michael

[keyplyr]

Hello MichaelGin and welcome to WebmasterWorld [webmasterworld.com]

1.) In some niches and for some sites where the content is similar or just not unique, Google has purged previously indexed pages. This has been going on for quite a while but may have just recently been applied to your pages. I don't know if anything on your end can be done to affect Google's indexing or not.

You could try changing page Titles & Descriptions and altering the content somewhat. Many sites make the mistake of have pages that compete with each other.

2.) How long has it been since the structured data was crawled? Maybe this will be included in the next algo update. Some things get updated pretty fast, others take a month.