I always saw Stoicism as “things around you are going to be really screwed up and panicking about it will make it worse”

The first part of that sentence is opposite to what the author here suggests.

both "screwed up" and "perfect" are judgements calls/perspectives, and panicking isn't going to change things (panic doesn't necessarily make something worse either)

I think panic almost always makes things worse. There's a reason that in an emergency, the first piece of advice to people is "don't panic".

almost is the key term here, yes, it depends on the situation causing the panic.

Panic always makes things worse

you can't think of an example where it doesn't? I can. I'm not saying there is any virtue to it, but panic can subside without having had negative side effects on anything other than your mood