Wifi Calling Keeps Disabling.

I enabled Wi-Fi calling on my iPhone, but I've been experiencing an issue where it keeps disabling by itself. Sometimes, I receive a notification stating that "Wi-Fi calling is not supported," and other times, it simply turns off. I tried resetting my network settings, but the problem persists. I've identified that this happens when my device connects to a Wi-Fi network without internet access, which triggers the automatic disabling of Wi-Fi calling. This also occurs when using a public Wi-Fi network with a weak router that fails when many people are connected, causing my iPhone to disable Wi-Fi calling. This behavior should be more like VoLTE, which doesn't automatically enable or disable itself. Additionally, after updating to iOS 17, some features, like voice isolation for cellular calls, do not stick, and I have to manually re-enable them after each update.