Hi, why is my Iphone XS Max loses network connection daily?

Try to optimize the range of the mobile network, see this Apple article:

If you see No Service or Searching on your iPhone or iPad

https://support.apple.com/en-us/HT201415

Check the Wi-Fi network, see the following Apple articles:

Connect to Wi-Fi on your iPhone, iPad, or iPod touch

https://support.apple.com/en-us/HT202639

See this Apple article: If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network

https://support.apple.com/en-us/HT204051

Recommended settings for Wi-Fi routers and access points

https://support.apple.com/en-us/HT202068

If you need help with your Wi‑Fi password

https://support.apple.com/en-us/HT204070