Brought home new kitten, older cat won’t eat

Background: Brought home a new kitten 2 days ago as we have a 1 year old cat and were hoping to give her a new friend. Have kept them in separate rooms throughout.

I noticed yesterday she didn’t touch her dry food and also refused her wet canned food. I even opened a churu which is her absolute favorite, only to have to force her to eat it. This morning her food from yesterday has been left untouched, and I opened a new can of food and she refused it again. I opened another churu, and she’s once again refusing it. I don’t want her stomach to be left empty and I don’t want her to throw up or have any other digestion issues.

Plan is to try to get her to eat, and maybe move her food to another location in the house that’s further from the kitten’s food and contact the vet if she doesn’t eat by tonight. How can I distinguish between her not eating because of stress from the kitten and something more serious like a blockage?

Any suggestions / similar experiences? I’m feeling very desperate 🥲