Most of the website pages are not indexed by google

Hello, I uploaded a website about a month and a half ago, and only 30% of the pages on the website have been indexed by Google. These aren't even the most important pages of the site.

Could the issue be with the content of the site in question? Here is the website. In terms of performance on PageSpeed Insights, the score is good though (evereything is green) i don't undrestand


What should I do to get Google to index all the other pages/articles? Thanks in advance