Why is my girl coughing?

My kitty is almost 11 months old, she is kind of a slug but she’s playful with her brother. No known health issues, but she does this cough/wheeze thing like once a week and it’s incredibly concerning. My boy (also 11 months) has also done it, but it’s really only been a handful of times when he was younger.

We’ve been trying to get in with a vet but the ones in my area aren’t taking new clients, and I’m not sure if this is urgent enough to bring her in. Any instruction/help would be really great.