I received my Z Fold3 on Thursday which is on July too with the same CsC as you.
Because security updates are generally sent with software updates and the Z Flip3 and Fold3 are on the most recent I'm guessing we'll see the next security update when the next software update is pushed out.
Normally I would expect to see BTU csc on a phone supplied by Samsung but this time round we have what looks like the European version.
Updates are also sent out in waves dependant on region, phone model and serial number.
I too hope we see an update soon as Security updates are indeed important.