OnePlus 8T launched Globally on March 2020. It has a setup of cameras which is good enough. Camera setup of both Oneplus 8T and Oneplus 9R are exactly same and identical. Stock camera does very good job . But still people want a working Gcam with good tuning of colors and natural Google photo processing . Here is the Working Google camera for both oneplus 8T and OnePlus 9R.
Oneplus 8T and 9R Camera
Rear camera
Wide (main): 48 MP, f/1.7
Ultrawide-angle: 16 MP, f/2.2
Macro: 5mp , f/2.4
Depth: 2 MP, f /2.4
Front camera: 16 MP, f/2.4

Oneplus 8T and 9R Gcam Download
Gcam 8.2 Greatness and XML – Download
HOW TO LOAD XML FILE :-
1) Download XML
2) Open your preferred GCam
3) Double Tap in between Camera Shutter Button and Camera switch button
4) Find the downloaded xml then tap on it and apply
NOTE : slowmotion , ois may not work . check this website frequently for updated gcams