Is there anything I can do to make my cat more comfortable during the summer?

Firstly: I live in the Southern Hemisphere. Yes, it’s summer here. We have Christmas in the summer. I don’t live in America.

My country usually doesn’t have very hot summers, but this year has been ridiculously hot and I think my cat is really feeling it (very lethargic, not eating as much as before, etc)

She has free roam inside and outside (so if either one is too hot, she can move elsewhere), lots of fans going full blast, curtains closed most of the day, and she always has a full bowl of cold water, but I’m worried she’s still getting too hot

I know she’d probably act a lot more out of character if she was suffering from the heat too much, but I’m still so paranoid that she’s hiding any discomfort

I’ve had her for a few years now but we haven’t had a summer this hot in a long, long time

So, does anyone have any ideas of things that I can do to make her a bit more comfortable?