"crawled - currently not indexed" - Question

I started a blog in Jan of this year. I've been creating original, high value content (2-3K words), following Yoast plugin's guidance when writing the content.

I've been able to rank on the first page for a bunch of the keywords I was targeting. But some of my posts have been labeled as "crawled - currently not indexed" in GSC. Obviously I want these indexed.

Today I requested most of the pages be indexed (there was a limit), some haven't been crawled since Jan/Feb/March so maybe that will help. I added some internal links to the pages where it made sense too.

I noticed that the category version of the web address (think website dot come slash category slash blog post) is indexed but the regular web address (website dot come slash blog post) is not indexed. This isn't for every not indexed blog post but I was wondering if this is why some of them are not indexed bc google sees it as duplicate content?

I'm not sure what to do next because most of the online resources don't have great advice. Any help or advice is appreciated!