Huawei Nova 3i has some uniquely advanced features that make it win the battle against Huawei P20 Lite and Asus Zenfone 5. Huawei Nova 3i firstly have a dual primary (16+2 MP) as well as dual front (24+2 MP) cameras which is really good for portrait shots. Secondly, it has more battery capacity and the best HiSilicon Kirin 710 processor.
These are the best camera phones under Rs. 20000. (You can also check the complete specs with links).
Oppo F3 Plus 6GB RAM - The Oppo F3 Plus provides a 16MP primary camera, which is accompanied by dual-color LED Flash and Exmor-RS CMOS sensor for superior quality photography. However, the principal attraction of the device is the 16MP+8MP dual camera setup up front, which offers a f/2.0 aperture and comes with screen flash to aid low-light selfies.
Nubia Z17 Mini Limited Edition - The Nubia Z17 Mini Limited Edition offers a great photography experience with its dual (13 MP + 13MP) primary cameras. Other camera features are an Exmor-RS CMOS sensor, phase detection autofocus, continuous shooting and High Dynamic Range mode (HDR). The 16 MP front camera that gets a 2.0f aperture which is capable of producing excellent quality selfies.
Asus Zenfone 3 ZE552KL - The device sports a 16MP rear camera that has OIS, phase detection as well as laser autofocus, RGB sensor, Exmor-RS CMOS Sensor, dual tone LED flash and has an aperture of f/2.0. Accompanied by an 8MP front-facing camera for selfies and video calls. Both, these cameras can capture brilliant quality shots in varied lighting condition.
Xiaomi Mi A2 is a lot better phone than Huawei Nova 3i and that too at a much affordable price. Both of them almost similar specifications apart from that Xiaomi Mi A2 supports Quick charging but lacks expandable memory option.
Honestly speaking, fast charging is the most relevant and important feature these days in phones. You can charge your phone fully within minutes while you are getting ready to leave your home. No, Huawei Nova 3i supports fast charging.