The Google Pixel 3 XL is the P-OLED capacitive touchscreen, 16M colors, 8 MP, f/1.8, 28mm (wide), PDAF & 8 MP, f/2.2, 19mm (ultrawide), no AF camera phone combination of 2019, a one-two punch when it comes to offering an expansive, color-rich display and photos your friends won’t believe came from a smartphone.
It has the dual front-facing speakers, Qualcomm SDM845 Snapdragon 845 chipset, and 4GB of RAM as the one-hand-friendly Google Pixel 3, But the Google Pixel 3 XL version is the one to consider for its larger 6.3-inch bezel-reduced OLED screen and higher-capacity 3,430mAh battery.

AOSiP OS stands for the full form of Android Open Source illusion Project. It is a quality custom ROM based purely on Google AOSP source since 6.0 release. Twisted with the latest features and blended with stability. We strive for perfection and it shows. Now you can experience the real Android Stock Experience with this ROM along with many new addition features.
Download Google USB Driver
Download Android Pie 9.0 Gapps
Download the AOSiP OS ROM for Google Pixel 3 XL
Download the TWRP Recovery.img for Google Pixel 3 XL
Download the TWRP for Google Pixel 3 XL

How to Install AOSiP OS on Google Pixel 3 XL
1➔ Copy the AOSiP OS ROM & GApps Zip files for Google Pixel 3 XL to your device. 
2➔ Restart your Google Pixel 3 XL into the TWRP recovery
  • Turn off your Google device.
  • Press & hold the “Volume Down + Power button” at the same time for about 5 seconds.
  • Release Held key when the Fastboot Mode appears on your device.
  • Use volume buttons to navigate the “Recovery Mode” option.
  • Press the Power button to confirm Recovery Mode boot.
3➔ Click Wipe and scroll down and choose advanced wipe and swipe to confirm Wipe.

4➔ Click Install and scroll down and choose AOSiP OS ROM Zip and swipe to confirm flash.
5➔ Click Install and scroll down and choose GApps package and swipe to confirm flash.
6➔ Once the installation is finished, click on “Reboot System” to reboot your device.

7➔ That’s it ! you have successfully Install AOSiP OS on Google Pixel 3 XL With New Android 9.0 Pie. Enjoy....