Joanna Jana Laznicka: They dont think the content is valuable. They already index other similar content and it bring no more value to serp
Michael Martinez: Your internal linking is weak. You could add an HTML sitemap that links to all your posts. That may help a bit. The site looks like it`s still new, as the posts only go back to late November. It could be you just haven`t earned enough links from other sites for Google keep everything indexed. Does Google Search Console show that it has discovered any links to the site? Don`t look at 3rd party link research tools.
Fabian Petersen: Michael Martinez Google search console states 2 external links and 295 internal links.
Michael Martinez: Fabian Petersen Are the internal links well distributed to many destinations or are only a small number of destinations listed? If your internal links are spread out among a lot of pages then you probably have enough internal linkage. Sounds like you just may need to earn some more external links.
Fabian Petersen: Michael Martinez yes I made sure that I distributed to many destinations. OK I will try to earn more external ones. Thanks for the recommendation! Also could it have to do with the indexing settings for tags? As I find it weird that the issue only concerns posts.
Michael Martinez: Fabian Petersen I think your site is still very new and just hasn`t earned much placement in Google`s search results yet. You could try Neil`s suggestion and use the URL inspection tool to resubmit some of the posts for indexing. If nothing else, it MAY tell you why they are not indexed (if there is a problem). I looked at the source code on several pages and saw nothing obvious. Your "robots.txt" looks good to me, too.
Michael Martinez: And I`m not surprised the posts are struggling to gain a foothold in the index. The site`s navigation favors the incidental pages (that is, in my opinion, how it should be). The pages with the most internal links are usually the ones that stabilize in the index first.
Neil Cheesman: Suggest go to Google Search Console and submit urls (your latest posts not indexed) - and have you submitted a sitemap?
Fabian Petersen: Neil Cheesman yes I have site maps in the search consoles. Also for the blog page which has been confirmed.
Neil Cheesman: Fabian Petersen Suggest crawling and submitting as some of those urls are not indexed
Why does Google show all my blogs pages, but none of the posts? Even after making sure that all pages, including the posts page are crawled? 
