For manual, high-intent pages, Google’s Indexing API remains the gold standard....

https://seo.edu.rs/blog/why-your-indexing-tool-says-indexed-but-gsc-says-otherwise-11102

For manual, high-intent pages, Google’s Indexing API remains the gold standard. When managing mass-scale link campaigns, third-party indexers often provide the necessary lift, with some services costing around $29 for 60 credits