The MIL-DIL is a very touchy relationship. If your mom asked you to do something you didn't want to, you could argue back, refuse, sulk ... whatever ... and it doesn't matter. A small squabble, a fight, and it will blow over with no hard feelings either side.
When a MIL asks you to do something, even if it is justified, and DIL doesn't want to do it, even if she has a good reason, like she has something else she needs to do, the situation is far more delicate. It's not that easy to just say no ... both sides harbour the issue in their heads for far longer. And the issues can build up in their heads and keep accumulating till they blow up.
The husbands have a huge role to play here ... if the husband makes it plain from day one that his wife comes first, then the MIL will back off, for fear of losing her son ... as Umaben had to do with Manav. Even now, she dares not be openly nasty to Chhanchhan ...
If the husband makes it clear that his mom is superior in the pecking order and has to be obeyed regardless, then most DILs really have very little choice ... unless they become obnoxious and vampish ... neither Ranjana or Sanjana are that.
Here both Manek and Manthan are not supportive ... Manek seems to be completely under his mother's thumb, while in Manthan's case, Sanjana herself is too simple and dumb to argue back. If she did, Manthan might be more supportive than Manek ... he has already shown himself to be more street smart and crafty than his other brothers. Probably that's why Umaben made sure to get him a dumb wife 😆
Great analysis. I agree how much your husband respects you and supports you makes a huge difference in how the rest of the in-laws treat you.