I know what you mean but honestly try not to focus on other writers too much. Make sure to promote your story as much as possible, on Instagram and on the forums. Maybe even requests shoutouts and ask groups to review your story 
However, R4R can actually be bad for the reader’s retention. For example if you do R4R with someone who has less episode as you do and this person reads only half of your story, it will have a bad impact on the reader’s retention.
If you are interested, you can check this out: I Will Promote Your Story On My Instagram!