Best Mobile phone in the range of 15K to 25K

I am giving some models which will be in your reach with the details. All these models are available in the market and even you can get from Amazon. I advise you to visit the showroom and see them and select.
1.Nokia 7 Plus - Specifications
Ram & Storage : 4 GB | 64 GB
Display : 6 (1080 x 1920)
Processor: 2.2 GHz, Octa
Operating System: Android
Primary Camera : 12 + 13 MP MP
Front Camera: 16 MP
Battery: 3800 mAH

2. Vivo V11 Pro - Specifications
Ram & Storage : 6 GB | 128 GB
Display 6.41 (1080 x 2340)
Processor: 2.2 GHz, Octa
Operating System: Android
Primary Camera : 12 + 5 MP
Front Camera: 25 MP
Battery : 3400 mAH

3.Oppo F9 Pro - Specifications
Ram & Storage : 6 GB | 128 GB
Display : 6.3 (1080 x 2280)
Processor: 2 GHz, Octa
Operating System: Android
Primary Camera: 16 MP
Front Camera: 25 MP
Battery: 3400 mAH

4.Huawei P20 Lite - Specifications
Ram & Storage : 4 GB | 128 GB
Display : 5.8 (1080 x 2280)
Processor: Octa
Operating System: Android
Primary Camera : 16 + 2 MP MP
Front Camera: 24 MP
Battery: 3000 mAH

5.Nokia 6 2018 - Specifications
Ram & Storage : 4 GB | 64 GB
Display : 5.5 (1080 x 1920)
Processor: 1.4 GHz, Octa
Operating System: Android
Primary Camera: 16 MP
Front Camera : 8 MP
Battery : 3000 mAH

6.Samsung Galaxy A7 - Specifications
Ram & Storage : 2 GB | 16 GB
Display : 5.5 (1080 x 1920)
Processor: Octa
Operating System: Android
Battery: 2600 mAH
Primary Camera: 13 MP
Front Camera: 5 MP

The Xiaomi Redmi Note 7 Pro is the best option for you. Redmi Note pro 7 comes with 48 MP+ 5 mp camera with unbeatable price tag of Rs.13999. The mobile set has storage facility of 64/128 GB . Redmi note 7 Pro is powered by Octa core (2 GHz, Dual core,) processor with 4 /6 GB of RAM with battery of 4000 mAh.

There are many models conforming to the specs asked by you and you can choose one among the - Xiaomi Poco F1 (around Rs 23000), Samsung Galaxy A50 (about Rs 20000), Honor Play 6GB (around Rs 23500), OPPO K1 (around Rs 17000) and OPPO F9 Pro (about Rs 20000).

Today the mobile phone market is crowded with various models in various ranges to suit the pockets of the individuals and it is in fact a difficult task to choose out a model which suits to our requirement.

Still as per the specifications mentioned by you we can go for a model out of the following options:

(1) OPPO F11 Pro -
Android v9.0 (Pie), Octa core (2.1 GHz, Quad Core + 2 GHz, Quad core), MediaTek Helio P70, 6 GB RAM, Display 6.5 inches (16.51 cm), 1080x2340 px, 396 PPI, IPS LCD, Camera 48 MP + 5 MP Dual Primary Cameras, LED Flash, 16 MP Front Camera, Battery 4000 mAh Super VOOC Charging 3.0 Non-Removable.
Approx. price Rs.24,990.

(2) Samsung Galaxy A50 6GB RAM -
Android v9.0 (Pie), Octa core (2.3 GHz, Quad Core + 1.7 GHz, Quad core), Samsung Exynos 7 Octa 6 GB RAM, Display 6.4 inches (16.26 cm) 1080x2340 px, 403 PPI, Camera 25 MP + 5 MP + 8 MP Triple Cameras, LED Flash, Battery 4000 mAh Fast Charging, USB Type-C port.
Approx. price Rs.22,990.

(3) Samsung Galaxy A8 Star -
Android v8.0 (Oreo), Octa core (2.2 GHz, Quad Core + 1.8 GHz, Quad core), Snapdragon 660
6 GB RAM, Display 6.3 inches (16 cm) 1080x2220 px, 392 PPI, Camera 16 MP + 24 MP Dual Primary Cameras, LED Flash, 24 MP Front Camera, Battery 3700 mAh Fast Charging, USB Type-C port.
Approx. price Rs.23,285.

(4) Xiaomi Poco F1 128GB -
Android v8.1 (Oreo), upgradable to v9.0 (Pie) , Octa core (2.8 GHz, Quad Core + 1.8 GHz, Quad core), Snapdragon 845 6 GB RAM, Display 6.18 inches (15.7 cm) 1080x2246 px, 403 PPI, IPS LCD, Camera 12 MP + 5 MP Dual Primary Cameras LED Flash 20 MP Front Camera, Battery 4000 mAh Quick Charging 3.0, USB Type-C port.
Approx. price Rs.21,999.

(5) Nokia 7 Plus -
Android v8.0 (Oreo) upgradable to v9.0 (Pie), Octa core (2.2 GHz, Quad Core + 1.8 GHz, Quad core), Snapdragon 660 4 GB RAM, Display 6.0 inches (15.24 cm) 1080x2160 px, 402 PPI IPS LCD, Camera 12 MP + 13 MP Dual Primary Cameras, Dual-color LED Flash, 16 MP Front Camera, Battery 3800 mAh Fast Charging, USB Type-C port.
Approx. price Rs.23,699.

The following smartphones would suit your needs and within your budget as well. They are the latest one and the better one for sure. You can check their specifications and features online.

Oppo F11 Pro

Vivo V15 Pro

Redmi Note 7 Pro

Honor V20

Asus Zenfone 5z

Poco F1

Mi A3, Mi 9SE, Huawei Enjoy 9s and Enjoy 9e smartphones are coming soon as well.

Among the existing one, Poco F1 and Asus Zenfone 5z smartphones are the only phones powered by Snapdragon 845 processor and enough specs compare to the rest that they are powered lower than SD845 chipset or SD660 mostly.