Hi,
It all depends on the keyword suggestion sources.
For the maximum relevance I would suggest not using the google, and trying to use post titles and taxonomy terms (order also matters): https://i.imgur.com/5SjIvD4.png
The keywords index from the index table is not taken into account, unfortunately most servers would not be able to handle that. We are working on a possible workaround for future release that may allow that as well.
The plugin can’t randomly guess/correct the words linguistically, that would require a 3rd party AI to make auto-corrections like the google search engine does. Unfortunately we can’t integrate those, they would be extremely for users and require a connection to a 3rd party service.
The suggestions are based on the existing data sources. A very efficient algorithm takes at most 50 000 phrases from the source and tries to get the closest possible matches within a threshold. It is fast and does not require a 3rd party service to pay for – however it is not as clever as an AI autocorrection.