Hello,
Thank you for contacting Rank Math.
The option to import using from a CSV file in Rank math is currently only available to Pro version users.
Since you seem to have the free version, you will need to Workaround this by importing the redirects to a plugin that supports this such as the redirection plugin then import from this to Rank math by heading to Rank math > Status & Tools > Import & Export under Other plugins section.
Hope this helps you. 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.