Hello,
If you want to enable port 22 for remote SSH connection, you can pretty much configure it in the WebUI of the router itself.
Navigate to System -> Administration -> Access Control, and enable the Remote SSH Access. (Find the attached image for reference).
However, if you have other use for opening port 22. Kindly change the default port on the same tab System -> Administration -> Access Control (e.g. 2222), for you to be able to allocate port 22 for other use.
Hope this helps, let me know the results.
Best regards,
Robert