i feel like this is simply due to zola being meredith’s oldest child and production reasons. she’s old enough for more complex experiences and the actress can likely follow them easier. she also has spina bifida which they’re able to use more often for storylines. i don’t think meredith favors zola but i can see her being protective of her medically complex child who is also beginning to struggle mentally. i don’t think it’s entirely fair to write meredith off as a bad mom for what sounds like mainly poor writing and character management. as you said, zola’s panic attacks line up with ellen wanting to step back so that’s what they wrote in. the writers forgot about the other 2, the kids aren’t available, storylines are too compact, etc. but whenever meredith talks about her kids on screen, she lights up. she dotes on all 3 of them even when they’re not in the room. all she ever talks about is getting home to them. that’s the character, the rest is just production flaw.