It's not just the Mayuri angle....yes, some people conflate her and Malini....that's one part of this. There's a whole other part where people literally judge the whole story based on who looks the part of wife/bahu, and who doesn't😆.....and also ofcourse, the blanket dismissal of this being a storyline about "cheating" the rightful wife - Malini😆.
But that is not the core audience....the core audience as you said, has latched on to the main nerve of the story which is Imlie.....the ratings wouldn't have been so steady if the audience didn't grasp that point regardless of whatever other cosmetic appearances are generated in the course of the drama. The loyal audience of the show is tuning in for Imlie's journey and her struggles....all the drama, the angst that swirls around the situations she's facing....her faith, her beliefs are the ones the audience sympathizes with as she's the one that's faced the biggest challenges and injustices in the story but always prevailed with resolve and a smile. What the writers have done effectively is woven in all the threads of the other equations into her journey very well....whether it's Adi, Malini, the Tripathis etc....all these threads weave into Imlie in some form or the other to keep the story moving....but she is the core that holds it all together. There is a reason the show is named Imlie😆.....and beyond all the noise and snap judgements, the core audience gets that.
I agree that the core audience connects the most to Imlie. It is her show & they relate to her journey, growth & her relationships through her. She is the core DNA around which every other character & set up is built.
Only a few people who are either Malini stan, part of other rival fandom or basically don't know anything about the show except that it is about 1 man & his 2 wives are very vocal on SM. These are few people but they attack so rabidly on SM that it makes us feel that are the audience not watching the show. But the truth is that the core audience are watching the show as it is being shown. Hence the steady TRPs.
.....but it will now all fall into perspective cuz the inconsistencies in her behavior that used to jar us will now all make sense.