Hello,It sounds frustrating to have your new iPhone 15 Pro Max not connecting properly to WiFi or experiencing slow data speeds. Here are ALL the methods I know and you can tryto see if these resolve the issues:
1. **Force Restart Your iPhone:**
Quickly press volume u , then volume down, and hold the side button until it get to the apple logo page. check theguided if you havetroublee doing this:Force restart iPhone - Apple Support
2. **Reset Network Settings:**
You mentioned you’ve already tried this, but it’s worth repeating if other steps don’t work. Go to **Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings**.
3. **Reset All Settings:**
This will not erase your data but will reset all personalized settings to their default values. Go to **Settings > General > Transfer or Reset iPhone > Reset > Reset All Settings**. ---Note that you will need to reconfigure your settings afterward, including network settings, keyboard dictionary, Home screen layout, location settings, privacy settings, and Apple Pay cards.
4. **Update iOS:**
Make sure your iPhone is running the latest iOS version. Go to **Settings > General > Software Update** to check for and install any available updates.
5. **Forget and Reconnect to WiFi Network:**
Go to **Settings > WiFi**, select your WiFi network, and tap **Forget This Network**. Then reconnect by selecting the network and entering the password.
6. **Try a system repair:**
if all that can't fix the issue try a system repair to see if this helps: Fix WiFi and Data Connection
7. **Disable WiFi Assist:**
WiFi Assist can sometimes cause issues. Go to **Settings > Cellular** and scroll down to **WiFi Assist**. Turn it off and see if this improves your connection.
8. **Reset Router:**
If you have access to the router, try resetting or restaring it. This can sometimes clear up any issues with network connections. if it's not the issue try
9. **Contact Your ISP:**
If the problem is specific to your WiFi network, there might be an issue with your internet service provider (ISP). Contact them to ensure there are no outages or issues in your area.
If none of the above steps resolve the issue, I recommend reaching out to Apple Support or visiting an authorized service center for further assistance. They can provide specific guidance based on your device model and iOS version.
Good luck, and I hope your connection issues are resolved soon!