Thanks for the clarification on this. I have an iPhone using iOS 18 as well. Not experiencing any issues with connecting to the app or streaming while on the same network as my cameras.
What Router and Provider are you using? I am asking because a community member had issues and it turned out to be related to their Router and setting it for High Security vs Normal Security. Here is the link:
In addition, you can try the Beta Release to see if that corrects your issues. To become a Member, follow the steps in this link: Become a Beta Tester
You can always roll back to the Prod Version easily with iOS. You install the Beta via Testflight and the Prod via the App Store