Contact your dealership for pricing, many will price match and if purchased from them fit FOC taking care of any reset of windows etc... Plus you know it will be the correct specification and dealer backed warranty.
The screen will switch between day and night mode depending on light levels and headlamp switch position.
Check you Nav handbook for details but if you go to Menu-Display you will see the settings available.
If you don't have the handbook download from Lexus website
https://www.lexus.co.uk/owners/about-my-lexus/manuals/#manuals-form
Do a search on this forum regarding OTA updates breaking speed camera alerts ..
There should be an option on the website to download to pc and onto a USB?