This usually is not about indexing speed, it’s more about crawl prioritization vs perceived value.
Google can discover pages in minutes, but indexing depends on whether the page is worth allocating index space right now compared to millions of other new URLs.
From what I have seen, slow indexing on new blog posts is often caused by a mix of below factors
Weak internal linking like new posts sitting in isolation instead of being part of a strong cluster
No existing topical authority on the domain yet
Similar or overlapping content across multiple posts, Google delays choosing a canonical winner
Low engagement signals on similar pages in that section of the site
Crawl budget being spent elsewhere on the site tags, archives, thin pages, parameters
One thing many people underestimate is that Google doesn’t just index pages, it indexes patterns of value across a site.
So if the site has a history of thin or repetitive content, new posts get queued longer, even if they are technically fine.
Indexing speed is often a reflection of internal importance, not just technical setup.