Hey Pratik,
I think that won't be necessary. It was a freebie (Related Pages by Kyle) from maybe evanto or something similar (I don't remember). It wasn't updated for a loong loong time now. I was using it since 2015, I suppose. It is not even available now. I did a google search, returned nothing. It was doing the job, so kept using it. Somewhere in my mind, I always wanted to migrate to something else, but then the task at hand kept me involved.
In fact when you suggested the health check, and the whole idea of troubleshooting, in the very first attempt I enabled everything else and disabled it, did the trick.
I am having mixed feelings at the moment! I should have first tried to check myself, before coming out on the fb group and this forum that Rank Math did that, but at the same time, I feel it had to happen this way. I finally got rid of that old set of code(that conflicting plugin)
Thanks for all your help! Thanks for your time!
