Hello,
Thank you for contacting Rank Math and bringing your concern to our attention. I’m sorry for any inconvenience this issue may have caused you.
I’ve checked the about page, and it is returning an error 404.
Since it’s already showing 404 error, it may take some time for Google to remove them on the search results page. Unfortunately, there is no exact time when will Google recrawl your site to read the page that is already deleted.
In case you wanted important/specific links to be removed immediately, you can use the page removal tool in your Google Search Console account. This process is known to take about 24-48 hours to remove the URLs upon submission.

Here’s a link for more information:
https://support.google.com/webmasters/answer/9689846?hl=en
I hope that helps.
Thank you.
Thanks for the clarification!
Hello,
Glad that helped.
Please feel free to reach out to us again in case you need any other assistance.
We are here to help.
Thank you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.