Inlaws broke our smooth mealtime routine. How do I get my 9mo back on track?

So my daughter is 9 months old and we've been doing solids since she turned 6 months. It took a few weeks to get into a rhythm but now mealtimes had become one of the smoother parts of our day. She sits in her high chair, we put food on the tray, she does her thing.
Then my inlaws came to stay for 10 days. They're lovely people but they have very strong opinions about how babies should be held constantly and mealtimes were no exception. Every single meal, one of them would insist on holding her in their lap at the table. I said somethng twice and had to hear that this is how we raised three kids' response so I eventually just let it go 'cause I didnt have the energy for that fight on top of everything else. They left 5 days ago. My daughter now screams the moment I try to put her in the chair. Like a full meltdown. She went from sitting happily to absolutely refusing the chair in under two weeks.
I know this is probably just regression and she'll adjust again but I'm exhausted and I dont know how to approach it. Do I just keep calmly putting her in every mealtime and wait it out? Send help pls.