iPhone 17 Pro Max frequently loses Wi-Fi signals and sometimes SIM coverage

Try and reset your network settings to see if the issues persist. If they persist, you might also want to force restart your iphone

1. Press and quickly release the volume up button.
2. Press and quickly release the volume down button.
3. Press and hold the side button until you see the Apple logo (this might take longer than 10 seconds).

Sirji-9 wrote:

My one month old iPhone 17 pro max often loses WiFi signals

Check your WiFi Router / Modem for --> Recommended settings for Wi-Fi routers and access points ...

If you connect to Wifi, doesn't necessarily mean you are connected to the internet. --> Internet not available WiFi and Cellular … - Apple Community

Wi-Fi Assist is on by default. This will automatically switch to Cellular Data if the device is not connected to the internet. About Wi-Fi Assist - Apple Support