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

https://www.mediafire.com/file/wlfbezc860k10jc/pdf-79883-62247.pdf/file

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