iPhone 13 Pro Max internet connection randomly drops from 500 Mbps to zero

It turns out the WiFi Assist setting being turned off did not solve the problem. It came back the following day. (I had posted earlier that it solved the internet connection problem). Therefore, I went back to your suggestion that I check the WiFi settings on my router and make sure they are according to Apple recommendations. The settings were good. However, I discovered my router satellites were a different firmware version than the router (I use Orbi by Netgear, with 3 satellites units). The system hardware was operating on 3 different firmware versions among the 4 devices (router + 3 satellites). So I went through the process of updating the firmware on all 4 devices. Now they are all on the same firmware version. Since then (2+ days), I have not had any problems with the internet connection dropping off intermittently on the iPhone.

Thank you for the reply. You need to realize that all other devices are able to connect to internet with 500 Mbps speed (dozens connected to WiFi and dozens more connected to Ethernet). Only the iPhone was having trouble. It started about 4 days ago. Before that, the iPhone connected at fast speeds without a problem. The iPhone is using iOS 15.6.1 that was recently installed. Maybe the problem started after that install. Fortunately, I searched the internet about this issue and found a solution. Here’s the Fix: On the iPhone Settings>Cellular>Scroll to bottom>Turn Off WiFi Assist. Since I did that 12 hours ago, my connection to the internet has remained fast (500 Mbps). No more random drops to 0-2 Mbps. This fix was found on support.apple.com but by doing a search on the whole World Wide Web. Apple reported the problem might be due to the WiFi Assist feature on the iPhone trying to automatically switch the iPhone from WiFi to Cellular network. The iPhone has worked fine since I purchased it September 2021, until the problem started about 4 days ago, and after the latest iOS install 15.6.1. Im not sure if the iOS caused the problem. The iPhone is working great now, after turning off WiFi Assist in the Cellular settings of the iPhone.