Some iPhone 17 apps stop receiving and sending data when connected to Wi-Fi

I recently bought an iPhone 17. I'm having issues with data transfers on some apps. When I connect to Wi-Fi, there are random times when some apps stop receiving and sending data. I noticed this because WhatsApp stops sending and receiving messages, Instagram stops updating its home screen and chats, and it even happened to me once in Pokémon Pocket, where every load took forever because it stopped receiving data. In each of those instances, I ran connection tests, getting results as if there was no problem, and at the end, the apps started working again. I've already tried resetting the network settings and even restarting the modem/router. The problem persists. Another note: when the problem occurs, if I switch to mobile data or disconnect and reconnect to Wi-Fi, the connection starts working again.