Whats with gayu

I hav watched scenes in its and bits..am totally clueles abt gayus behavior is she supporting vedika or is some othr story

I don't think this is about Vedika she seems to be resentful towards the family for how she and Vansh (Vivaan's son) are treated. She thinks they aren't treated like family because Vansh isn't Goenka blood and also they have hinted that somewhere Samarth may have not fully accepted Vansh. Gayu was displeased because chachi made that comment about Vansh him being all possessive about Kartik as she already thinks both she and Vansh aren't accepted as family members.

When Kairav enters the villa it's going to be fuel to fire with the Kairav vs Vansh track as Vansh is going to be jealous when Kairav gets Kartiks love and attention. This is going to finally lead to Gayu's outburst.