I bought my new iPhone 11 64gb about 3 months ago and if at night I leave it at 69 percentage and in the morning the WiFi switched on automatically I come with 49 percentage and I think the battery dies too fast and I’m afraid because my phone is new

So ~20% battery usage over ~8 hours means roughly ~60% for a day, so you’re getting about a day and a half with this iPhone.

That seems reasonable for an iPhone with the smaller battery. The Max models have larger batteries.

About the battery usage on your iPhone, iPad, and iPod touch - Apple Support

Batteries - Maximizing Performance - Apple

Use Low Power Mode to save battery life on your iPhone - Apple Support

About Optimized Battery Charging on your iPhone - Apple Support

But I'd plug it in and charge it overnight.

Please type your post again. I did not see any questions in there. I saw ONE run on sentence that did not make any sense to me. Please be more specific with complete sentences followed with questions so that we can try and provide some decent guidance. Thank You.

Axel F.

Having the phone lose battery charge overnight (unless you have it turned off) is expected. Why aren't you plugging it in at night? When the phone is plugged in overnight it automatically backs up to iCloud and is fully charged in the morning.

If you disconnect from a WiFi network from the Control Center, it will automatically reconnect in the morning. If you want to turn off WiFi, go to Settings>WiFi and turn it off.

It sounds as if you're phone is working as expected.